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Chapter Text

"Look! Mummy! I got my quirk!" The little toddler excitedly runs up to his mother, something wet and red cupped in his small hands.

"Oh?" Inko peers down at the practically vibrating boy, her green haired son rocking side to side with excitement.

"What is it darling?"

"I scraped my knee! A-and it really hurt- but- look! Look! You can see it move!" Izuku reaches up as high as he can, eagerly revealing the dripping wet crimson blob languidly pulsating in his hands. The thing arches up in one big breath, before it settles into a shape perfectly fitting her son's cupped hands.

It looks disgusting, a cross between coagulated blood and torn open muscle fibre. It seems to beat like a heart, slow and dying, little filaments of probing tissue gently tapping the edges of Izuku’s fingers before retracting and trying again a moment later. A slimy red substance clings to her son's wrists, slowly losing liquid as it bleeds red onto the ground, but trying it's best to stay in the child's too-gentle hold, red liquid defying gravity as it crawls up the boy's skin and returns to the crimson puddle in his hands.

"Izuku... what- what is that thing?" Inko brings a hand to her mouth, horrified, but trying her best not to show it.

"It's my quirk!" Izuku giddily reminds her, cradling it close to his chest and watching in fascination as thin little red tendrils reach out to probe his yellow All Might t-shirt.

"W-where did it come from?" Inko cringes, barely resisting shrieking in terror as Izuku brings it too close, the red liquid reaching out to touch the tip of his nose.

"I scraped my knee mummy, and it... it like came out of it." He explains confusingly, tilting his head to the side and watching with a childish glee as the red slime copies his movement, slushing to one side of his cupped hands.

"You scraped your knee?"

"Yeah!" The boy cheers, tilting his arms up and away as chucks out his leg, his knee sporting a rough looking scrape where his shorts couldn't protect him. The skin looks dry and strangely bloodless, but it's roughed up enough to make an ordinary toddler cry.

"It was small at first," Izuku goes on, bringing his hands down to his hurt knee and raising them up as he talks. "But then it kept drinking and drinking, and I feel kinda funny. But it's all big and strong now! It's like the size of a ball!" He cries out, rocking side to side again and even tapping his feet adorably. Her son always did have too much energy.

"It was just a little tiny dot when it first came out..." he muses, "I wonder how big it can get."

"Can you control it, Izuku?"

"Hm? Oh, uhh, not really, no." Izuku looks down at the squishy red thing, "it just does what it wants to, I think."

"Okay... uh, looks like we'll need to go to the quirk doctor." Inko worries her bottom lip between her teeth.

It's possibly the worst quirk she's ever seen, some kind of disgusting blob creature made out of what sounds like her son's blood... She hopes she's wrong about that, maybe he just explained it badly? What does it even do? Is it even safe to be around? It doesn't resemble any other quirks in their family...

She digs through her bag for a moment, searching for an empty plastic container from their earlier lunch at the park. She'd only left him alone on the playground for a few minutes, he's been so lonely ever since the other kids got their quirks and he didn't... She was hoping he was just a late bloomer, and perhaps he is if that squiggly red mess in her son's hands really is a quirk.

"Here, Izuku. Put it in this container." Inko holds out the plastic tub, her son hesitantly obeying and dropping the squirming red blob into the offered container. Inko watches queasily as he wipes it off his fingers, droplets of sticky red slime reabsorbing into the pulsating whole.

Izuku looks upset, his little green tinted brows furred. Her little boy isn't upset often, he's usually so happy and cheerful, smiling just like All Might. But right now he looks so serious, watching uncomfortably as his quirk is sealed away in a plastic food tub, the red sludge rattling the container before settling with a death-like stillness.

"It doesn't like that..." Izuku pouts.

Inko carefully puts it in her hand bag anyway, somewhat concerned that it will leak out and escape, spilling disgusting red blood everywhere.

"Come on Izuku, let's go wash your hands."

--

Demon Blood.

That's the name the doctor gives his quirk, poking at the thing with a pencil before reeling back as it snatches the pencil from him and snaps the lead in half, little tendrils shooting out aggressively. Tissue tries and fails to manifest, little black streaks of melanin and pale white calcium form in stringy single cell lines, but the tiny blood creature is too small to sustain larger growth, its energy diminishing more and more the longer it's kept away from Izuku.

They weigh it and measure it, (200g and 6cm wide), running it through an x-ray scanner and even exposing it to several common materials, water, carbon and heat, but it doesn't react much.

They want to keep it overnight, observe it in a petri dish and watch its cells either multiply or die off, but Izuku refuses to be separated from it for that long. He cries and wails and makes such an ordeal that Inko doesn't know what to do. Izuku, her precious Izuku, never throws tantrums, he's always so well behaved and sweet.

"No! NO!- g-give it- b-back-" he yells between stuttering sobs, little hands outstretched to the crimson blob going crazy in the sealed glass container.

"Doctor... I think it might be wise to let him keep it, I know you want to do more tests, but nothing has ever made Izuku this upset..." Inko weakly interjects. She's not thrilled about the idea either, doesn’t want that disgusting little thing anywhere near her baby, but Izuku’s happiness and wellbeing always comes first.

It rockets against the thick perspex walls of the container, viscous body morphing and twisting as Izuku’s crying peaks, the little boy red in the face as tears streak down his cheeks. Everyone in the room startles as it snaps new thin fang-like teeth, the creature forming a gaping circular mouth in the centre of its small mass.

Despite how bad of an idea letting it out seems, the doctor still nods in agreement. A nurse hesitantly opens the lid on the creature, its frantic red tendrils reaching out to Izuku's awaiting arms. The little boy scoops up the red blob, still crying and sniffling even as it crawls across his skin and settles over his chest and neck, the boy hugging himself tightly as it squirms beneath his clothes.

The nurse is visibly disgusted, while the doctor tries his best to maintain his professionalism, a faint grimace on his face. Inko puts her hand on Izuku's shoulder, aiming for comfort, but sharply pulls away when the red creature touches her, its cold and slimy body making her shiver in disgust and wipe her hand on her skirt.

"We took a small tissue sample and were able to determine that it contains the same blood and DNA as your son. And exposing it to Izuku's blood increased the creature's energy. We believe it's a rare type of parasitic quirk, perhaps even a sentient quirk, but it's unclear how... intelligent it is." The doctor awkwardly finishes.

"The sample we collected shrivelled up and died in under an hour, it's unlikely it can survive for long if it's split apart. We'll have to conduct more tests in the future. I'd recommend Izuku logs all his observations in this notebook." The doctor hands Izuku a plain lined notebook, the boy accepting it wordlessly despite his still misty eyes.

"Write down everything you can about your quirk Izuku," the doctor instructs, "you'll know the most about it. It may change and grow as you do." Inko cringes at that, she can't imagine it growing bigger.

Izuku looks amazed, he cradles the notebook close, little tendrils of red peeking out of the collar of his shirt to touch it too.

"I'll write down everything!" The little boy declares with a fervour, green eyes bright and excited once more. He even starts rocking side to side again, the red sludge pricking under his shirt as it feels his heartbeat raise with excitement.

"We can be heroes together!" He cheers, giddy at the possibilities now that his quirk has finally manifested.

"Doctor..." Inko wrings her hands together, "what did you mean by parasitic quirk?"

"Ah well, it's quite simple really." The doctor looks at Izuku with an expression the little boy can't really understand, pity, disgust perhaps?

"It feeds on Izuku's blood to survive."

--

Izuku spends the next week constantly drawing and writing. He's got the week off from kindergarten to adjust to his new quirk. And while Inko frets and worries, Izuku spends his days playing with the creature, poking it and holding it, encouraging it to come to him when he calls, the little red blob rolling across the floor, clumsy and new like a baby deer.

"Mummy! Mummy! Look, it can be a square or a circle!" Izuku runs up to Inko with the slimy creature in his hands, the viscous red blood squeezing itself into an semi-orderly cube before expanding out into a lumpy sphere.

Izuku giggles as it repeats this, fascinated by the undulating flesh and squishy red blood. He's never really been afraid of his quirk despite how it moves so grotesquely, its surface a sticky red slime that breathes like a beating heart.

"I drew a picture of it in my book!"

"That's very good Izuku, um- why don't you go play some more, dinner will be soon." Inko waves her son away, cringing as the gooey creature lurches out of Izuku’s cupped hands, little red filaments sickeningly reaching out towards her.

"Okay! But, I think it's hungry... Can we feed it some dinner too?" Izuku tilts his head adorably.

He didn't really understand what the doctors meant when they told him it was a parasitic quirk. They only gave it a few drops of his blood, and that was enough to send it into a spasming fit, sticky red tendrils desperately searching for more. She didn't let Izuku watch that test, she was too worried that it would give her baby nightmares. It was bad enough that they had to use a needle to collect Izuku’s blood for their tests.

But... she also grimly hopes it will only feed on her son, though the thought sickens her, guilt eating away at her insides, but she can't stomach the idea that it might feed on her! Might bite her or stab her or do something unknown and horrible. She still remembers its terrifying needle-like teeth, the horror movie mouth in the centre of its amorphous crimson body, snapping and hungry. What if it hurts another child while looking for food? Is it safe to take to kindergarten or should she lock it up in a container at home? Izuku didn't seem to like being separated from it, but surely he'd get used to it?

"Alright honey," Inko weakly agrees. She doesn't think it will eat any of the katsudon she's made, but maybe she'll be pleasantly surprised?

Izuku runs off to keep playing with his quirk, happily plopping the red slime in the middle of a poorly made wood block castle. It pulses and ripples, body expanding to reveal a sharp toothed circular mouth, the nightmarish blob eagerly gnawing on a red coloured block. Izuku only giggles as it chews, making a game of it, he giddily places more blocks into its mouth, the creature spitting them back at him only for the little boy to try again.

--

It doesn't eat any dinner.

Katsudon may be Izuku’s favourite food, but his quirk doesn't seem very interested. Izuku plops the red squirmy thing atop the small bowl Inko prepared for it, but it just sits there, pulsing, but otherwise still. It doesn’t bother to manifest its terrifying needle-like mouth and after a minute its little filaments extend to the edge of the bowl, the creature probing its way back to Izuku, leaving the breaded pork and rice cold and untouched.

Izuku pouts, upset that his little friend didn't even try and eat dinner with them. As it crawls lazily across his hand and up his arm, he ponders what it might want to eat. It doesn't like meat or rice, or maybe it's just because it's cooked? Dogs and cats have special tin food, but his quirk isn't shaped like an animal, it's not really shaped like anything. It's closer to a slime mould as it stretches and wriggles, crawling across his skin like living blood.

"Mummy, it's still hungry," he whines.

Inko says something about trying some different foods later, but Izuku knows that won't work. It doesn't like human food and it probably won't like pet food either. He knows, deep down inside, that this creature, his quirk, needs him to survive. He's known since the day he tripped and scraped his knee and it crawled out of his skin, hungry and bright. Knows it subconsciously, innately, like one knows they have five fingers on each hand.

He thinks about the short time he's spent with his quirk so far, playing superheroes with it, bringing it with him in the bath, even going to sleep with it curled over his heart. There's some sick twisted compulsion that makes him want to feed it, makes him want to poke the tip of his finger with something sharp, like when the doctors collected his blood, so that it can drink the little drops of red and be all happy and bright again. He wants to give his quirk anything it needs, anything it wants. If it will just keep playing with him, if it will stay by his side and stop him from feeling so lonely. Mummy has been so busy at work, and daddy is never home anymore. Even Kacchan doesn't like him as much anymore, he wouldn't accept his help when he fell over crossing the log bridge over the stream.

They thought he might have been quirkless for a while, since he was already four and a half before his quirk finally manifested. People don't like it if you don't have a quirk, already some of the kids at kindergarten had started to exclude him, making up games he couldn't play because he needed a quirk to do so.

That night he stays awake for longer than he's allowed to. Staring up at the ceiling, feeling his quirk pulse and twitch where it's spread out across his chest, thin red flesh rising and falling with his every breath. He softly runs his fingers down his shirt, feeling his quirk reach up to meet his touch, growing excited, wriggling faster in response.

His quirk is special. He just knows it.

"You're still hungry." Izuku whispers into the dark.

He'd written a big long list of things his quirk might eat and so far every single item has a big red line through it. Everything he can think of is either stinky human food it won't want, or something inedible, like a rock or sunlight. He knows that plants eat sunlight, they use it to grow big and strong. But being out in the sun for too long makes his quirk all tacky and slow, it dries it out like an old wet sponge.

Izuku frowns, he feels like it's been getting smaller lately, leaving little crusty red stains on his bedsheets overnight and breaking into little pieces when it reaches too far during their games. It's slowly dying, and the thought makes Izuku want to cry his eyes out, his chest hurting at the very idea of it.

"What do you eat?" He wonders aloud, "do... do you eat me? Is that what the doctor meant." Izuku sits up in the dark, eyes blinking uselessly in his dim bedroom. The creature on his chest ripples in answer, little filaments curling around to hug his back.

"You can have it if you want... my blood... even- even if it h-hurts," Izuku whimpers out, scared it's going to be as painful as it was when he scraped his knee.

The little boy holds out his finger, nudging the writhing red sludge covering his chest. A dozen tendrils reach for his fingertip, the slimy crimson creature oozing out inch by inch until-

He gasps at the pinch of pain as little fangs sink into his skin, his quirk curling around his fingertip, small white needle like teeth peeking out as it munches and twitches.

His finger throbs in time with his heartbeat, the stinging area quickly going numb as it settles over his digit, inching like a worm up one knuckle, then two, until it's even wrapped around his palm. Izuku cries a bit as it drinks, his quirk pulsing and undulating, slowly growing bigger, veins bulging across its viscous surface, small tendrils reaching out to hold his hand still. The little boy can't help sniffling and weeping, even if it's stopped hurting. It's kinda scary, the way it ripples and swells, getting too excited to hold.

Cradling it close to his chest a wave of sleepiness rolls over him, making his vision swim as it drinks too much, too fast, for a little toddler to possibly supply. He doesn't know it, but there's an anticoagulant in its saliva, a substance that makes his blood all runny and thin, stops it scabbing and slowing down. The creature's fangs gnaw on his finger, ripping open skin and letting his runny red blood fill its starving mouth. It gorges itself on him, drinking until he's pale and sleepy, the beast only slowing when it realises its host can't give enough. The red sludge prickles in distress when it feels Izuku’s blood pressure fall, the boy slumping back in his bed, eyes lidded and breathing short and sluggish. He's too pale. Too pale!

The creature quickly pulls back, blood spilling sloppily all over Izuku’s All Might bedspread, his finger raw and red, skin sliced open in several places. Sticky red tendrils sling back to his skin just as quickly, letting instinct guide its actions as it smears thick transparent slime all over the cuts. The little boy groans, as the crimson creature settles heavily over his chest, needy and trembling. It's desperate to hear the thrum of Izuku’s heartbeat, slippery red slime crawling under the boy's pyjamas to wrap around his tiny torso.

It feels like a big hug, Izuku thinks, dizzy and weak as the red sludge ripples beneath his clothes, a few errant tendrils clinging to his wounded hand. It's twice the size now as it was before, he notices. Thick bands of veins rise and fall with their every breath, the slippery creature still wriggling and twitching, slime pressing stubbornly against the underside of his jaw, right over his pulse even if he doesn't realise that's why it's lingering there. It has too much energy for sleep, but after everything Izuku’s been through there's no way he can possibly keep his eyes open.

"Are you still hungry?" He whispers weakly. "I hope you feel better now..." the little boy's eyes close.

"We're gonna be best friends... I w-want us to be heroes together..." he presses, trying his best to stay awake just a bit longer, "you have to grow up big and strong," the little boy insists, relaxing under the touch of a thick red tendril brushing against the side of his face.

Chapter Text

"Izuku! What happened to your hand!" Inko almost drops the bowl of breakfast she's holding, eyes wide in horror at the state of her poor baby's mangled fingers.

Izuku tucks his hand close to his chest, half hiding it as he sheepishly mumbles. “I just slept funny.” It's a pathetic excuse and Izuku knows it, but he can't think of anything else to say.

She gently grabs his arm and brings his injured hand closer. The skin is red and irritated, thin slices littering his index finger. There are a few stray cuts dotting his other fingers, the back of his knuckles and even scraping across his palm. There's old dried blood on his hand, it's kind of streaky and thin. A strange dry clear substance has been smeared across his skin, stitching shut some of the larger wounds. It looks painful and raw, as though he'd tried to shove his hand through a cheese grater.

His icky little quirk ripples under his shirt, almost as sheepish and uncertain as he is. It doesn't take long for Inko's stern gaze to crack him, her baby boy looking away shyly as he explains the creature's first attempt at properly feeding off him.

Inko's heart plummets. Of course, the source of her baby's pain is that foul little quirk again. Sticky red tendrils slither out the sleeve of his long sleeved pyjama shirt and curl around his fingers possessively. Although Izuku somehow seems to find it a comfort, a shy little smile tugging on his lips.

"It was just hungry," Izuku stresses, oh so innocent, oh so ready to believe the best in everyone and everything. "It'll be more gentle next time." He insists.

Placating words don't soothe Inko's distress. She quickly abandons breakfast to drag Izuku to the bathroom where their old first aid kit is just underneath the sink. He looks a little pale, walks a little shakily, just how much blood did that monster take!

"Come on honey, let's get some bandaids on those cuts." She says, trying her best to stay calm despite the fear and worry bubbling up inside her. She sits her son down on the little bathroom stool, gently holding his hand to inspect the damage.

Izuku doesn't seem to be in any pain, he just sits there quietly, content to sit with the wriggling crimson creature peeking out of his bed shirt.

Wiping off the dried blood and that strange clear stuff is her first priority. She runs a clean cloth under warm water, gently dabbing away at it until the blood is gone and most of the tacky clear stuff is dissolved. His cuts unexpectedly start bleeding again, Izuku fidgeting in mild pain and discomfort.

All too quickly Izuku realises that the clear liquid made it hurt less and that the strange slime acted like a flexible band-aid! He smiles a little, his quirk is so smart!

"Izuku, does it hurt?" She asks while carefully wrapping a roll of white bandages around his shredded index finger. She hopes it won't scar, but it looks pretty bad...

"Only a little," Izuku responds as she finishes wrapping his hand, smiling a little at how funny and big his finger looks now, covered in a wad of thick white bandages. His mummy even puts a few All Might themed band-aids on the smaller cuts littering the rest of his hand.

His quirk emerges to investigate, the viscous red creature brighter and more nimble than yesterday as it slinks out from underneath his clothes to condense in the palm of his hands. Izuku automatically cups his hands together to support it, the veiny red slime so big he’s barely able to hold all of it in his hands. It ripples, little filaments probing the area, the creature somewhat upset that its repairing slime has been removed preemptively, its host's wounds not yet properly healed.

Inko looks on warily. It's so much bigger than before, pulsing and bright. Where yesterday it was around the size of an orange, now it's as big as a melon! No wonder her baby looks so poorly, that blood sucking monster took way too much.

"I think I need to feed it often," her little boy says to her horror. "It got too hungry... if I let it have a little bit every day, I don't think it will make me feel so sleepy."

The sludge creature returns to his chest, curling over his throat and shoulder atop his clothes this time, and Inko shudders when Izuku doesn't even react. He wanders back to the kitchen, eager for breakfast while Inko is stuck where she is, kneeling on the bathroom floor. How can she even process this? Her son's quirk actively harms him, and yet he doesn't seem to care, seems excited by it even. Where it writhes and twists, pulsating like a foul abomination from hell, Izuku just grins, giggling without a care in the world. Inko feels her eyes grow misty, terrified of what the future may bring, what if it gets so big it kills her son? Will it keep on living? Murdering anything with blood it comes across and feasting on their flesh.

Can it eat animal blood? She could buy some pig's blood from the butcher and try that. It might keep Izuku’s quirk alive without it feeding off of his body.

She commits to buying some, to at least try and alleviate the pain of Izuku’s quirk. She doesn’t want to bandage any more bite wounds caused by his quirk.

--

All Might is his most favourite hero ever. But despite this fact, his quirk still chooses to engulf his favourite All Might figure in sticky red slime, quickly enveloping the red and yellow toy much to Izuku's distress.

"Hey!" Izuku cries, eyes watering as it scurries away from his outstretched hands.

How can they play heroes together if his quirk keeps eating his toys!

The red blob wriggles and twitches, eventually spitting out a now much wetter All Might toy. It twists and pulses, reaching up up and- wow! It looks just like All Might!

Izuku cheers as his quirk takes the miniature form of the number one hero, crimson red sludge shaped like a replica of his toy, complete with the little V pointing hair tufts and All Might's classic victory pose, one fist raised in the air while the other rests on his hip, confident and proud.

It looks a little gross, the slimy red thing still pulsing and wet, but just this small attempt at connecting with Izuku's hero obsession has the little boy ecstatic, flapping his hands excitedly as he grins his biggest smile.

"Wow! Can you move?" He asks, squealing with joy and giggling excitedly as it does a little staggered walk, mimicking the humans it's seen to the best of its ability. He laughs as it stutters, All Might's hand still posed high in the air.

"Just like All Might!" Izuku stands on his tippy toes, copying the slimy thing's All Might pose.

"Never fear, for I am here!"

Inko giggles from the doorway, glad that despite the strange and unsettling quirk he's ended up with, he at least still acts like a happy little kid. Still playing, still laughing, what more could Inko want?

"Izuku? You'll be going back to school on Monday, okay." Inko says. Izuku nods, he knew he'd have to go back to school eventually, even though playing all day with his silly slimy quirk is way more fun.

"Alright mummy," he concedes, holding his hands out for the red sludge, its slimy body reaching up up up, tendrils of red gripping onto his fingers and wrapping securely around his hands. He squeals in delight as it sloppily hauls itself into his hands, slimy tendrils curling around his wrists and crawling up his arms.

They've worked out a few little tricks together. Izuku’s able to guide the slime wherever he wants by either reaching out his hands, or offering an arm for it to slip down to the ground. He oddly likes the feeling of it touching his skin, it's not too hot and not too cold. Usually strange textures make him feel icky, but his quirk is just so fun to touch, he could spend hours just kneading and poking it. The first time he tried smushing it between his fingers he was so scared he was going to hurt it, but his quirk seemed to actually like the attention, prickling happily and pushing more slime between his fingers for Izuku to play with.

Inko looks queasy as it settles on his shoulder, thin little tendrils creeping under the collar of his shirt and hugging around his back and the side of his ribs.

"I can't wait to show Kacchan my quirk!"

--

Izuku holds his mummy's hand as they walk to Kindergarten, a few tendrils of his quirk curled around her wrist as well. She'd made a funny sound when it first touched her, looking kind of scared, but she didn't let go of Izuku’s hand, bearing it's creepy wet touch for the sake of her child.

It wriggles occasionally with second hand excitement, feeling Izuku’s elevated heartbeat and responding in kind. Inko thinks it's disgusting wrapped around her wrist, but the feeling of it squirming beneath his shirt just makes Izuku giggle.

Eventually they make it to the daycare, Inko kissing Izuku on the top of his head, her lovely baby boy giggling sweetly. She puts his tiny bag in its designated cubby, labelled with his full name and a sticker of his choosing, All Might themed of course. Izuku waves her off, his slimy quirk mimicking the action and waving along as well with a slimy red tentacle.

Before long Izuku is sitting in class excitedly, he can't wait to finally share his quirk, to be allowed to join in on the games all the other kids play, to finally play with Kacchan and not be pushed away again.

Soon the teacher calls him up to the front of the class. It's practically tradition to give a little show and tell about one's quirk when it emerges. Most of the other kids have already got their quirks, he's the only one who's already four, but didn't have a quirk yet.

"The doctors call it Demon Blood, but I think it's just a silly little friend," he excitedly holds up his quirk, all the crimson red slime crawling up his arms and gathering in a large ball in his hands.

"Ew!" One kid calls out, "it looks kinda gross" another says. "I think it's cool..." is mumbled quietly, and before he knows it the whole class is in an uproar, chattering and talking. Fingers point at it, kids squealing loudly when it moves, its little filaments wriggling out in exploration. One kid starts crying at the sight of it, terrified of the scary red creature.

"Quiet voices everyone," the teacher reigns in control of the classroom again.

"It's made out of my blood." Izuku excitedly shares, not really noticing how half the class looks at him strange, their opinion only souring at the finer mechanics of Izuku’s sentient parasitic quirk. A range of disgusted noises ring out as kids shake their heads, comparing it to old chewing gum or something mouldy growing in the back of the fridge.

The teacher awkwardly congratulates Izuku, instructing him to go sit down so that today's lesson can begin. Izuku happily plops down next to his best friend Kacchan, his quirk settling happily in his lap. It reaches back with thin little tendrils when he uses his fingers to play with it, the crimson slime wrapping around his digits comfortably. His class doesn’t seem too excited to meet his quirk, but he's sure they just don't know yet how fun it is to play with. His quirk is fascinating to watch move, to touch and play with, it's responsive, creative, passionate and just a bit silly. It really likes blood and it really likes him, and he's sure that if they just play with it too, they'll see that the crimson slime isn't so scary after all, even with its dozens of needle-like teeth and its veiny undulating body...

Kacchan glares at the red blob in his lap, poking it cautiously and reeling back when it pokes him back, sticky filaments probing the air and brushing against skin.

"It's gross." The spiky blond says bluntly.

"Kacchan-"

"What does it even do!" Kacchan scowls, crossing his arms grumpily, "how can we be heroes together if you have a useless quirk."

Izuku falters under the stern gaze of his best friend.

"Um..." he weakly answers, hands wringing together anxiously. "Well... I don't know yet, I'm still writing down everything it can do and- I- I don't know everything about it yet..." Izuku explains, hugging his quirk close and relaxing when he feels thin little tendrils curl around his body in response.

Kacchan huffs, turning away from the boy and crossing his arms over his knees.

"My sidekick can't be a weakling," the boy grumbles, and Izuku feels all that worry and fear come rolling back in.

He finally has a quirk and it's still not enough...

That day Izuku doesn't get invited to any games outside, in fact, it seems worse now. Instead of just not having a quirk yet, he has a bad one, a villainous quirk, something he didn't even know was possible until the kids teased and mocked him for it.

Ugly, they call it. Gross, scary, evil. Izuku tries his best to not let it get to him, but the sting of rejection after rejection has him crying and hugging his quirk in the reading nook, pathetically hiding away from all the other kids.

This isn't how he thought it would go at all...

Izuku gingerly retrieves his special notebook from his little yellow bag. Flipping it open to a blank page he starts to write down his feelings, a mix of sadness and disappointment spewing out into the badly scribbled words. Through crying blurry eyes he draws a picture of himself as a superhero to cheer himself up, adding his precious squishy quirk at his side, doing the same cool pose as him. He wishes with all his heart that the other kids would find his quirk as awesome as he thinks it is.

Probing red tendrils curiously touch his damp cheeks, sensing his distress, feeling the salty liquid against its flesh. He's not sure if it can really see like he can, or if it can sense the world around it, rippling red skin feeling the vibrations in the air. Can it smell? Can it taste? Izuku has so many questions inside him, he's always filled with curiosity for the world and he thinks his quirk may have that in common with him. It likes to probe and touch, likes to feel what's going on.

"It's okay," Izuku soothes, but now that he's really thinking about it, he isn't sure if it can even hear him speaking? Maybe it can, because the longer he talks the more clingy it gets.

"I don't need anyone else as long as I have you." He affirms, little hands gently stroking down its slimy back, giggling as it tickles his finger with delicate little filaments.

Sometimes he thinks it looks like the roots of a bright red tree, other times like a splatter of paint or a fascinating alien creature. Regardless, he loves his quirk, he realises that now. It doesn't matter if no one else likes it because it's his. He loves it.

Chapter Text

It's hungry again and it's only been three days.

Izuku can feel its agitation in the way it settles against his skin, slimy red flesh rippling and twitching as it presses against the places on his body where his pulse thrums the strongest.

The little boy rocks back and forth impatiently as they wait in line at the grocery store. The supermarket checkout beeps monotonously, it's kind of irritating, but if Izuku focuses on curling the tendrils of his quirk around his fingers, he finds it isn't as noticeable.

"Mummy... can we go home now?" Izuku asks, feeling his slimy quirk wriggle across his chest, the graze of sharp thin fangs reminding him how much it hurt when it bit him. He's a little bit scared to feed it again, but he knows he has to, they both have to grow up big and strong if they want to be heroes together.

"I'll feed you later," he promises quietly, whispering so only his quirk can hear him.

He tugs on the end of her sweater, delicate red tendrils reaching out as well to copy his movement. Inko half turns to him, "alright honey," she says. "We'll only be a bit longer."

The little boy whines, but relents, going back to impatiently waiting. The little toddler sways side to side this time, trying to distract himself from the restless squirming wriggle of his quirk beneath his clothes.

"Mummy-"

"We can go now, Izuku. Here, hold this for mummy." She passes him a lightly filled grocery bag, Izuku excitedly grasping the handle with both hands and jumping up and down just because he can. His quirk reacts to his excitement, little filaments reaching out to grasp the plastic bag too, the red sludge rippling quickly where it's spread flush against his chest.

"Let's go! Let's go!" Izuku giggles, following after his mother and grumbling when she walks too slowly.

When they finally get home they have dinner together, Izuku scarfing down his portion of sesame tofu, veggies and rice, and quickly running off to his room to finally go play heroes again with his quirk.

Rustling through his toy box Izuku finds his favourite All Might figure and his cool new Gang Orca toy.

"Let's play rescue heroes!" Izuku cheers, peering down as he lifts the top of his shirt. He giggles when his quirk reaches for the Gang Orca toy he's holding, slithering out from the neckline of his shirt. He smiles, watching little red tendrils curl curiously over the black and white edges of the plastic toy, twitching as it grasps it.

"Kacchan always makes me the villain... but we can both be the heroes! Here, let's save Teddy from the earthquake!" He pulls out his plush bear as well, bringing out the little wooden blocks again and artfully placing them on top of the stuffed toy.

But while Izuku may have eaten a filling dinner, the grotesque crimson creature writhing across his torso is still starving.

Izuku doesn't expect the pinch of sharp fangs sinking into the back of his neck. He gasps, knees hitting the ground in shock, his All Might toy clattering to the floor. Slippery red tendrils reach out from his back and spread out across his neck and chest, inching across the lower half of his face as it latches itself securely to the fast beating vein on the side of his neck.

Izuku stumbles forward, kneeling on his hands and knees as his quirk takes a big long drink, body rippling as it feeds. The little boy whimpers, the sharp pain teetering off as numbing slick is smeared across his neck, needle-like fangs pumping it underneath his skin, the anticoagulant solution making Izuku bleed more freely. Giving and giving, he's such a perfect little host.

It's more precise this time, isn't as messy and wasteful, only puncturing the skin with a handful of teeth. The slime bulges and ripples, veins rising across its surface as it sucks hard, the gush of fresh delicious blood quickly filling its viscous body.

This time it's over before he realises it, his quirk tenderly lapping at the bleeding wound, thick transparent slick quickly sealing the punctures. The room seems to spin, a ringing noise filling his ears as his tiny body slowly adjusts to the sudden drop in blood pressure and unexpected dizziness. He can feel the weight of it on his back, heavier now, he thinks, and it takes everything he has in him to be happy about that rather than scared. Regardless, he feels tears bud at the corner of his eyes. He can't help sniffling, even if the pain is gone, it felt so scary to not know it was coming.

Izuku sits back with his legs folded underneath him, breathing funny as he sniffles, but soothed by the tender way it strokes his cheek, tendrils brushing through his hair in a way that reminds him of his mother. It hasn't even been long enough for the cuts on his hand to heal, his finger still covered with hero themed band-aids. But now he has a new bite mark to add to his growing collection.

Mummy was so worried when she saw his hand. Even though he told her it didn't mean to hurt him, at least he thinks it didn't. Maybe... maybe he won't tell her about this, maybe she won't notice?

Izuku wipes his eyes, shakily picking up his All Might toy, only to drop it again when his hands tremble too much. That seems to be the last straw, sending Izuku into an all out crying fit, sobbing as quietly as he can.

The crimson creature ripples against his skin, sending strong bright red tentacles out to grasp his toy, effortlessly picking it up and putting it in Izuku's hand. Wriggly tendrils curl around his hand, constrictly softly until he's properly holding his All Might figure. His quirk keeps his grip steady, his crying soon dying down, writhing tendrils wiping away his tears and nudging him back into the game.

He thinks it might be sorry. Might feel bad for making him scared and hurt, but he can't know for sure. It is a squishy amorphous sludge creature after all, he hasn't even known it long enough to be able to read its emotions. He can't really communicate with it, can only hug it close and hope it stays kind and sweet like this, hope it won't get bored with him, hope it will keep being his friend and not abandon him like Kacchan did...

Izuku sniffles as he plays, rescuing Teddy san silently and trying not to wince when he moves, his neck aching steadily as the numbing slick slowly wears off. Crimson tendrils help clear the little wooden blocks, mimicking Izuku’s All Might toy and by making the Gang Orca figure 'pick up' the blocks.

Through teary eyes Izuku smiles softly.

--

After only a month since his quirk manifested, Izuku comes out of kindergarten bawling.

The little boy hugs his quirk as tight as he can, sobbing too much to get a word out, red in the face with a runny nose too. Inko doesn't know what to do. He'd been fine when she dropped him off at preschool this morning, excited even, though she knows he hasn't made any new friends yet. And Katsuki is invited over less and less these days.

But now he's a mess, his sticky red quirk spreading possessive wiry tendrils mindlessly across Izuku’s clothes, grasping for any part of the boy it can reach. Some of the other parents and kids stare, murmuring and whispering, but Inko puts it to the back of her mind while she deals with this newest crisis.

"Oh honey, what's wrong?" She kneels down to his level, hesitantly putting a hand on his shoulder despite the way his quirk curls around her fingers.

"Th-they- th-" Izuku sobs, words disjointed and garbled as he rocks himself side to side, his quirk squeezing around him in response, holding him as close as it can.

Inko worries as it constricts, terrified it's going to hurt him, but he only calms under its touch, slowly gaining his heavy breathing back under control.

"They- lock-locked it up..." he cries, whimpering and wet, hands stressfully running through its slimy body, the creature arching up into his touch, practically purring as he pets it.

"What?" Inko frowns, not really understanding.

"The- the teacher!" He says, sniffling loudly. "The teacher- p-put it in a cardboard box and- and I couldn't hold it all day!"

"Oh honey," Inko soothes, "it's alright, you're together again, just take a deep breath," his mother tries to calm him down. Izuku nods, shakily breathing in and out, nice and slow.

"I'll go talk to the teachers," Inko decides. She scoops him up in her arms, the sticky crimson creature curling a few tendrils around her too. She tries not to let it get to her, but the feeling of its wet stringy limbs touching her is possibly the worst sensation she can think of.

When she gets to the kindergarten reception and finally is able to talk to one of Izuku’s caretakers, she's not very impressed.

"His quirk was scaring the other children, Midoriya san." Izuku's teacher explains patiently, "it's such a frightening quirk, surely you understand. Perhaps it's best if Midoriya leaves it at home tomorrow?"

"Well..." Inko falters, she had come in here so confident and righteous, certain that they were at fault for making her poor baby cry, but... She can sort of understand where they're coming from. She'd had the same thoughts herself when Izuku’s quirk first manifested.

"What if we came to a compromise," Inko tires. Her son is still sniffling in her arms, burying his head into the crook of her shoulder, she rubs a hand up and down Izuku’s back, hoping he'll calm down and stop crying soon.

"I know it can hide under his clothes, what if he keeps it out of sight?"

"Hmm, that might work. If Izuku can keep it under control and away from the other children, we'll let him continue taking it to school."

The next day Izuku seems to have particularly low energy when she picks him up from kindergarten. Still worried that they're going to take his precious quirk away from him, and depressed that he can't let it explore and learn as he does, the squirmy little thing staying bored and still beneath his clothes all day...

--

Problem after problem seems to arise because of Izuku’s quirk.

"Oh baby, you have so many marks on you..." Inko frets, delicate fingers tracing the old scabbed over cuts littering his son's neck and arms.

Izuku is having a nice warm bath, bubbles float along the surface and he's even got a few floating bath toys with him, a hero patrol boat carrying the water rescue duo Water Hose. Her son pushes the little boat forward, the plastic toy bumping into the wet crimson creature poorly floating in the shallow bath water. It hisses at the boat, circular mouth opening to reveal a dozen needle sharp fangs as it pushes the toy back with a portion of its amorphous body. Izuku just giggles at the display, his quirk isn't truly angry since its slimy body is still calm and smooth, it would be all prickly and veiny if he'd actually upset it. He smiles, he's getting better at understanding it.

"Izuku, honey, how often are you feeding your quirk?" His mother presses. Izuku turns his body to answer her, pausing for a moment to think.

"Well... whenever it's hungry," he says simply, shrugging. He turns back around as the little plastic boat grasps his attention again. The crimson creature reaches out a few tendrils, stabilising in the water as it anchors itself to the little boy's outstretched legs.

"I see..." Inko worries her bottom lip. She's noticed her son getting paler, he's more sleepy and less energetic than he used to be. Perhaps she should take him back to the quirk specialists, maybe they can figure out a less taxing feeding schedule? Or maybe he needs some dietary supplements? Having his blood syphoned so regularly can't be healthy for a growing boy.

It's times like this that Izuku’s quirk seems more like a leach than a proper quirk. It just takes and takes and doesn't seem to give anything back. It feels like a curse.

"My cuts go away after a few days, mummy," Izuku explains, "I think it makes the hurt go away sooner."

"Really? So all of these are from the last few days?" Inko pales, that's way too much!

"Yup." Izuku cheerily confirms, oblivious to his mother's mini freak out behind him. "It's growing really quickly so it needs lots and lots of food."

And it has grown quickly, the crimson menace is probably at least twice as big as when it first manifested, able to shoot out longer and more dexterous tentacles, its vibrancy and stamina far increased.

Inko worries. Everyday she worries more and more. She commits to taking him back to the doctors soon, surely they can help.

"Izuku... I don't want you to feed it every day." She says. "It can't be good for you."

"But mum!-" he spins around in the bath, eyes wide, mortified.

"Only every two days! You need a break from feeding it, you're still growing yourself." Inko puts her foot down. Just putting that small rule in place already makes her feel better.

The next day they visit the general quirk doctor clinic. They mostly only handle quirk registry updates and first quirk manifestations, but it isn't too hard to get a referral to a quirk dietary specialist.

They take a bit of blood, run some tests, and consult with another specialist on summoning and sentient quirks. Izuku’s quirk is a special case, it has difficult unknown parameters. But with the information they've gathered, Izuku even bringing his poorly written quirk journal with him, they are able to come up with a plan to improve Izuku’s energy levels and keep him on track for a healthy development.

The tests come back and they find out that her poor baby has an iron deficiency, and at this rate his growth will be stunted. His quirk won't eat pig's blood, she's tried that one at home to no avail and the results are the same here. It also seems to have a lacklustre appetite when given a small amount of her own blood, having either grown a particular taste for Izuku’s blood, or perhaps being incapable of digesting blood from anything other than its host.

Iron supplements. They're a must now for Izuku, who is going to be bleeding fairly regularly for the foreseeable future. It's unclear if his quirk will continue to grow at the rate it has been, but it's estimated he'll need to 'feed' it at least once a week to sustain its existence. They don't really know if it can die, or if it can regenerate or re-manifest from Izuku’s blood, but her child doesn't seem keen on testing that out, furiously hugging his quirk close when it's even mentioned.

He needs to take one iron pill every day with food, the doctor adding in a multivitamin and calcium supplement to assist with the nutrients his quirk steals from him. They're told to monitor the situation, but ultimately there isn't much they can do, unless they want to starve his parasitic quirk.

It's not quite the answer she wants, but it's the best she can do right now. Her two day rule between feedings leaves his quirk agitated and hungry, but it's the best she can do to protect her baby.

Chapter Text

Izuku whimpers, only just holding back tears as he gently prods at the fresh burn on his forearm. The skin is pink and raw, throbbing painfully. He doesn't understand what he's doing wrong. Why won't anyone play with him? Why does nobody like him?

His first day at elementary school and there's already been an incident.

No matter how hard he tries, pleading, reassuring, begging his quirk to settle down, to stop hissing and spitting, he can't stop it from snapping at the other children. A group of kids had ganged up on him, Kacchan taking the lead, as usual. They spent ages just teasing and prodding his sticky red quirk, the other children screaming and giggling every time it reared up in anger and frustration. Izuku had tried his best to ignore them, to pull his quirk back, little fingers threading uselessly through its crimson body. But they'd just kept pushing, until finally one threw a small rock at it.

It snapped.

The rock missed the slime, its dexterous body compressing beneath the throw. But it hit Izuku in the arm, making the little boy flinch and yelp, half in surprise, half in pain. And that was all it took to reveal fangs not yet shown, the creature's hideous gaping mouth stretching wide and large, thin needle like teeth lining a dozen separate rows inside its mouth, like a tunnel of death.

The kids screamed and yelled, calling it a monster, calling him a monster. The next rock thrown was aimed at him on purpose. Izuku just covered his face with his arms and curled into a ball around his hissing angry quirk.

Kacchan bravely approached his curled up form, blasting Izuku away with a few pops of his quirk and consequently claiming the credit for defending the class against his 'villainous quirk'.

It's not fair. He didn't even do anything. His quirk has never hurt anyone! It doesn't even like blood that isn't his.

He sniffles loudly, wishing he could just go home. Crimson red tendrils gingerly trail against his forearms, feeling the heat emanating off his fresh burns, the skin tight and red. Izuku cries a bit as it smears thick transparent slime across his arms, putting the numbing healing substance on the burns that it usually uses when feeding off him. He appreciates the effort, so grateful that he can rely on his quirk to be there for him.

He curls up into a ball, wrapping his arms around his legs and resting his chin on his knees. Little red filaments inspect the rest of his body, searching for any more wounds, they spread out like a web of crimson roots, tapping softly against his skin. He's a bit wet and sticky by the end of it, the crimson slime patching up a few scratches from the rocks, but Izuku doesn't mind. He doesn't think there's anything his quirk could do that would truly make him mad... He'd always forgive it.

"They think you're gross." Izuku mumbles, leaning back against the wall of the elementary school building and holding up the crimson sludge in his lap. It doesn't fit as well in his hands as it did when it was baby new, it's thick viscous body so much larger and heavier now between his fingers.

"I don't care what they think... I love you." Izuku affirms and he finds he means it. Regardless of how creepy or ugly the slimy red blob is, wiry tendrils always reaching, white fangs gleaming and threatening, the surface of its body shiny and wet and occasionally veiny. It pulses in his hold, breathing like a beating heart and Izuku finds himself smiling. He plants a little kiss on the top of it, dark green eyelashes fluttering closed, soft and sweet right on the forehead, just like his mummy does when he has a bad dream. Although, its amorphous shape makes it hard to kiss the top of its head...

How can they not find his quirk as fascinating and cool as he does? Can't they see the potential? His quirk could do so many different things! He's already learned that its spit has healing properties.

His quirk ripples, tentacles curling over his fingers. It... seems to hesitate, like it might be thinking. Izuku tilts his head, watching it convulse and throb, viscous body pulling in tight, tendrils wrapping around one another, bones forming and shifting for the first time ever. He'd theorised it could create bone and musculature, considering it made fangs to feed off him, but to see it grow and shift before his eyes is stunning.

Izuku gasps, holding up his quirk's best attempt at 'cuteness'. It has four legs and a little nubby wagging tail, its jaw opens the wrong way, unnaturally vertical, but that's okay, it's the effort that counts. It also doesn't have ears, just little holes where they could form, eyeless and skinless, its familiar fangs line a horrifying mouth that splits open from snout to chest.

It looks like a small skinned dog, but Izuku loves it more than anything.

"Puppy!!" Izuku squeals, hugging his slippery red quirk as close as he can. Viscous slime sticks to his face in long tacky lines, but Izuku doesn't care. It licks at his face happily, or at least tries to, mimicking the dogs they see at the park or walking along the street. It looks a bit like his neighbour old man Ito's little old dog, but... more wet and squishy. Izuku feels little tendrils reach out and hug him back, his quirk still functions as normal, despite being shaped like a small canine.

"Did you do this just for me?" He asks with wonder in his eyes, his crimson quirk just wagging its new nubby tail and relaxing in his lap.

"I love it!" He squeaks.

"What if... what if I named you Puppy?" Izuku proposes, running his hands down its back as though it were a real dog. His quirk twitches and moves beneath his touch, still wet and slimy, but there's a sturdiness to its form, muscles and bones giving it the capacity for faster, more powerful movement. It can stand beside him now, they can run together and play more games, Izuku’s analytical mind already imagining a thousand scenarios and possibilities.

It seems to like his response, its tentacles picking up his increased heartbeat, observing the way he smiles, the giddiness in his voice. It likes this. Likes being the reason for Izuku’s happiness. It feels good when its host does. Its crimson body ripples in satisfaction, a rough purr emanating from its half formed chest, flesh barely clinging to bone.

Yes. Puppy is a suitable name if only because Izuku chose it.

His quirk slithers closer, tendrils probing at his neck, pushing aside fabric. And Izuku happily tugs his uniform further down, readily providing it full access to his tiny body. The crimson canine splits its face in two, right down the middle, another leach-like mouth emerging from the centre to suction itself to his throat, burrowing into the crook between shoulder and neck. Izuku barely flinches at the pain, well accustomed now to the feeling of fangs sinking into his skin.

He pets it as it drinks, the crimson body anchoring itself further with a few more sturdy grasping tentacles, the tube-like mouth softly convulsing as it gulps down his sweet fresh blood.

The whole process is over in less than a minute, but Izuku finds himself more relaxed and calm, the puncture wounds swiftly sealed with thick tacky slick. Puppy licks at his neck a bit longer, pulling together its 'face' again, and wagging its tail stiffly. It's tongue isn't quite right, more of a wet pink tentacle than a dog's broad flat tongue. It's too long and too coily, but Izuku doesn't mind.

"Who's a good boy?" Izuku smiles, grabbing the crimson canine's face. It pants at him, tentacle tongue hanging out of its sideways mouth, fangs rippling, its eyeless face fleshy and wet.

"You are!" He giggles, happy that Puppy doesn't seem to mind playing the part of a dog for him.

His quirk is so cool!

--

Mummy doesn't like his quirk, at least, that's what Izuku suspects. She is reluctant to touch it and often uncomfortable when it's around. At first, Izuku doesn't really notice all that much, until the day he brings home his slimy red quirk and proudly shows her its brand new 'puppy' form. She flinches away from it, hand held to her mouth, 'that's great, honey'. But it's not. It's not great because mummy doesn't like it, she tells him to put it away, to put 'Puppy' away, once he explains its new name to her.

He's feeling despondent, idly pushing around the food on his plate and begrudgingly taking his collection of hard to swallow pills, only because he knows it will help Puppy grow up big and strong.

He asks Mummy if Daddy is coming back soon from his business trip, but she makes up some excuse about him working extra hard right now. Izuku just wanted to show his father how big his quirk has gotten, show him its cool new doggy form! But that doesn't seem likely to happen anytime soon. He was hoping his mother's reaction would be different than the kids at school, they all screamed and cried, Kacchan calling it an even bigger monster now, although it hadn't really changed much in size, just rearranged some details. If anything it's smaller now, denser, but nobody seemed to care. They all took one look at its strange mouth full of scary sharp teeth and immediately told the teacher on him, claiming he was doing it on purpose to scare them.

Dinner is a quiet affair, Inko spending her time avoiding looking at the crimson tentacles curling across the top of the table, while Izuku tries his best to finish all of his greens.

"Mummy... Do you like my quirk?" He manages to ask, hesitant and fragile. And it takes a moment too long for his mother to respond, Inko pulling on a strained smile as she weakly reassures him.

"At least you have a quirk, Izuku. Things could be much worse." And wow, that came out wrong. She grimaces.

Izuku nods. It could be worse he supposes, although he's not sure how.

Afterwards Inko lets him watch some Mighty Kid cartoons, the All Might themed show is usually his absolute favourite, but today he just feels exhausted. He didn't tell mummy that the other kids were mean to him, she'd only ever agreed with his teachers when they'd said his quirk was scaring everyone who had the misfortune of looking upon it. It seemed pointless to pester her, knowing nothing will change.

He's not really paying attention so he doesn't notice when Inko enters the room, his mother startling at the sight of Puppy latched onto the crook of his neck, crimson tendrils draped possessively over his body.

She screams at the sight of blood, using her telekinesis to throw a nearby book at the pulsing creature feasting upon her precious child. It jolts at the unexpected object hurled at it, hissing and prickling. The hit knocked its fangs from his skin, ripping open the punctures messily. Izuku cries out, confused and afraid and Puppy immediately curls around him defensively, stretching its body as far as it can to protect its host from any more attacks.

Inko puts a hand over her fast beating heart, gradually calming down after the initial panic. She can hear Izuku crying behind the crimson sludge, its rattling hissing teeth bared and threatening towards her. In the dim light of the living room, she can only just make out the blood coating the side of its form, extra wet and slippery where it had been jostled from its secure grip on her child. It had looked terrifying biting her baby, those needle sharp fangs clearly visible as it greedily drank from him.

She slowly approaches, "oh baby are you okay?" Inko asks, but her only response is more weepy crying and 'Puppy' going feral, hissing and snapping and still trying its best to look as big and threatening as possible.

She can't believe that's what it looks like when it feeds... She realises then that she hadn’t actually seen it eat before.

"I'm sorry honey, it just... it just scared me a little, okay?" She gets as close as she dares, Izuku’s quirk manifesting tendrils with sharp spines on the ends that she's never seen before. They're pointed threateningly towards her and she kind of feels like she deserves it, considering that she made her poor baby boy cry.

"Do you want to stay up tonight to keep watching your cartoon?" And while usually Izuku would jump at this opportunity, tonight he just wants to go to his room and sleep, cocooned nice and safe in the lukewarm embrace of his quirk.

"N-no thank you..." Izuku whimpers out, "I'm- I'm gonna go to bed now." He says, scooping up a still hissing Puppy and hurrying to his room. Inko's insides fill with guilt the more she processes what she'd just accidentally done, left standing alone in the living room.

--

Izuku adores his quirk's new form. They can play even more games together now, like tag or hide and seek. The little boy enjoys dragging his oddly shaped quirk to the playground by the park, chasing Puppy across the tanbark and squealing as it follows behind him down the slide. Puppy wags its stubby tail, panting and rippling as Izuku flaps his hands excitedly, pointing in awe at the massive cicada he discovers sitting at the base of a tree.

Inko quietly watches them from a park bench not too far away, ready to leap into action if anything were to go wrong.

"No! Don't eat it!" Izuku cries as Puppy's face splits in half, the crimson creature's horrifying leech-like tongue lingering threateningly over the large bug.

Her baby boy is growing up so fast.

She leans back on the bench, sighing tiredly. It hasn't gotten any easier to deal with Izuku and his quirk. The teachers have phoned her several times complaining that Izuku’s frightening the other kids, that he doesn't pay attention in class and he's antisocial, unwilling to even try and make friends, clearly preferring the company of his icky little quirk. It's harsh, but she can't help but agree with them. Katsuki never comes over anymore, and Izuku doesn't have any other friends to her knowledge. Her poor baby is all alone and there's nothing she can do about it...

Maybe he'll get better with time? She can only hope and fret, and wonder where it all went wrong. How did Izuku even get this quirk, there's nothing like it on her side of the family, and his father's side, well... She assumed they were all fire and heat related, but maybe there's some more strangeness there than Hisashi was willing to admit?

Her pondering is abruptly cut off by the sound of Izuku crying, her son having tripped and fallen while running across the grass. She shoots up to go help him, but the dog shaped sludge is already licking Izuku's scraped knee clean, it's slimy touch calming her son down far faster than Inko ever could.

She deflates a bit, watching her child hug the slimy skinless creature with an adoration she doesn't know how to compete with…

Chapter Text

Winter makes Puppy extra clingy, Izuku thinks its crimson slime might be losing more body heat a lot faster than him. It gets cold and brittle during winter, moving more sluggishly and laying dormant across his chest far more often than usual.

His quirk can often be found buried under their kotatsu, slow and lazy, just content to 'sleep' in Izuku's lap, although he can't really tell if it's even sleeping. It seems to particularly like Izuku’s All Might onesie, wriggling into the hood whenever he puts it on. Izuku thinks it's the coolest and softest thing he owns, and he wears it twice as much in the winter, just to keep Puppy warm and happy.

Izuku slips on his thick outside winter clothes, Puppy condensing into a lump buried in his scarf, and Izuku giggles at its silly actions, nuzzling into it happily. His notebook is almost completely full! He'd spent the last half a dozen pages sketching Puppy from every angle, capturing everything from the way its fangs look to the unique slimy texture of its hide. He loves drawing pictures of its dog form, but struggles to keep the proportions realistic, he always draws its long windy tongue curling around the page just because he thinks it looks fun.

Puppy doesn't like the cold, but he can ‘tol-er-ate’ the heat, a new word mummy helped him write down in his notebook. Izuku found that out by carefully observing Puppy during the different seasons and asking it how it feels. He writes all his results in his notebooks, he's been learning new words too! But the crimson blob is still incredibly hard to read, communicating its thoughts with a ripple of its red fleshy 'skin' and tugging at him with a tentacle using varying strengths for different levels of urgency. Izuku tries his best to be kind and considerate, just like how the teachers say at school, but if Puppy wants something it's more likely to simply take it from him, instead of asking. Izuku has been practising requesting food with it, grabbing a tentacle and tapping it against his neck before encouraging it to bite, his quirk slowly associating the gentle tapping command with food, and even surprising Izuku by initiating a request first. It helps Izuku be less startled when it bites, lets him know it's coming at the very least, and so far it's helped them avoid accidentally feeding again during school time.

It only happened once, but it was so scary! Puppy had wriggled to the front of his school shirt, slime rippling with agitation and hunger. He didn't really pay it any mind, trying his best to focus on the letter writing task he'd been assigned. But then it bit him, Izuku yelping in surprise as it latched itself to a fresh vein, jaw wriggling to stretch out the wound, starting a healthy supply of blood to the parasite. The little boy cups the creature to his chest, feeling it pulse beneath his touch, drinking steadily. And he simply went back to work, his left hand occupied with supporting Puppy, but his right free to continue practising his writing.

"Midoriya, what are you doing? We've talked about this, no quirk use during class!" His teacher calls out, leaning to the side to try and see what's going on from his desk.

Izuku curls in on himself, embarrassed at being singled out during class.

"It's just hungry, I'm sorry," he tries to explain his reasons, but that never works with adults, they don't want to know why, they just want to be mad at you.

His teacher stands up and Izuku dreads what's about to happen, subconsciously shrinking down into his chair to try and make himself look smaller. His classmates whisper and gossip, pointing at the bits of red slime they can see around the collar of his shirt, his quirk bulging beneath his clothes, wriggling softly.

Kobashi Sensei grabs the lock box from underneath his desk. When Izuku's been particularly 'bad' his elementary school teachers will confiscate Puppy, locking his quirk up for the rest of the day, until it's hometime and Izuku can have his teary reunion with his precious Puppy.

"Come on, Midoriya. Hand it over." Sensei demands, holding out the container expectantly. The teachers hate touching it without gloves, and it also seems to respond more calmly when Izuku is the one moving it, rather than some stranger yanking it away from its host.

It ripples beneath his shirt, tendrils tightening around Izuku’s torso, its grip possessive and territorial, utterly unwilling to move while it's feeding.

Izuku shakes his head, "I'm sorry, Sensei," he tries again. "It's still eating, I can't move it."

"What?" The man asks. He places the box on Izuku's desk, peering closer. "I swear Izuku, if you're making things up again-"

"I'm telling the truth! See!" he unbuttons the first two buttons of his school shirt, revealing the slippery wet creature latched to the corner of his throat. Its body undulating and twitching, veins thick and prominent, its fangs adjusting occasionally to keep the flow of blood fresh.

"Oh my god, you need to go to the nurse's office!" The teacher panics, eyes wide at the sight of blood beading up around the puncture wounds.

"No, I'm-" Izuku tries, but he's already being grabbed by the wrist, Kobashi Sensei dragging him out of the room while the whole class watches the display in a mixture of sick fascination, fear and outright disgust.

"The monster got Midoriya!" One of his classmates cries.

"It's ‘cause he's such a weak Deku!" Kacchan throws out, "his own quirk attacks him!"

Izuku's eyes grow watery and damp at the cruel words. He's brought diligently to the nurse's office where together they try to gently pry Puppy off his neck. But it isn't gentle at all. Its fangs slide out best when it decides it's done feeding, but the adults won't listen to him! Eventually they just pull it off him, gloved fingers digging into its slimy flesh, hooking under the side of its mouth and tugging it away. They pry off its tendrils, forcefully separating them and Izuku cries while Puppy hisses furiously, tendrils flailing, body convulsing and wriggling, trying to squirm back to its host.

Puppy only gets a few licks in, barely able to apply its wound sealing slick, before it's ripped away and shoved into the locked box on the other side of the room. It rattles in its container, hissing and gurgling, the sound of Izuku’s crying only making it freak out more.

The nurse wipes his bleeding throat, disinfecting it with a stinging solution and placing a big cotton patch against his skin, sticking it down with uncomfortable medical tape. Izuku just whimpers quietly, knowing he won't get Puppy back for at least the rest of the day, if not longer.

He was so scared that they wouldn't let him keep taking Puppy to school after that, but his mother fought them on it until they begrudgingly allowed him to keep bringing Puppy to class. Izuku was banned from feeding Puppy on school grounds on account of ‘illegal quirk use’, and Inko agreed, just happy to have reached some kind of compromise with the school administration.

Izuku shakes his head of those uncomfortable memories, focusing instead on walking through the brisk winter air. His mummy is walking by his side, once hand loosely curled around his gloved one.

Soft motes of snow drift from the sky, airy and light and Izuku points to one excitedly, squealing with joy as they start to fall around him. His quirk bravely reaches out a cold red tendril, grasping for the snowflake and making Izuku laugh as it slips right through its grip. It's host giggles and laughs, mission accomplished.

Izuku loves the snow, even if his quirk doesn't. He thinks it looks so pretty and he likes how quiet it is. The little boy happily trots down the path, shaking his mother's arm every time he jumps into a fresh patch of show.

They're going to yet another doctor's appointment. His mother is constantly worried that Puppy is dangerous to him, always anxious that his bite marks will get infected, that Puppy might transmit some disease or take too much of his blood. He tries to reassure her, but Inko won't really listen to a child who knows nothing. Even though Izuku knows it's safe and good for Puppy to feed on him. It feels good even when his quirk drinks from him, the pinch of fangs sinking into his skin reassuring in a way few things are in Izuku's world right now.

Today they're testing the strength of his veins to see if there has been any degradation due to frequent bleeding and injury. He's fine! But no one believes him. Puppy knows when he's feeling sore and picks a different spot to bite him. It likes to drink from his neck, but his arms and legs are easily accessible as well. His torso is preferred, and Izuku thinks that's the best spot too since he often wants to hold it close as it drinks, still intrigued by the way it feeds and moves.

They usually try to feed in private... Nobody else understands!

"Come along Izuku, we're going to be late," his mother hurries, tugging him closer. She drags his attention away from Puppy still trying to catch snowflakes with its tentacles, his quirk plopping a tendril on his head when he laughs at it too much.

Puppy settles back down in his scarf. It's cold. Izuku feels cold too when he looks up at the tall concrete quirk counselling general practice building.

--

Eight years old is super old! Izuku thinks. It's his birthday today and mummy is going to take him to the beach to celebrate!

Izuku spends the morning squiggling away in his third hero analysis for the future notebook. The first one was for Puppy, but after he started writing about his own quirk, Demon Blood, he decided to try adding more entries on other heroes. He's still obsessed with heroes, he can't imagine becoming anything else when he grows up, despite what people say. Demon Blood is a great quirk! And he's going to use it to save anyone who needs saving, even if they have a scary quirk, or a bad quirk or if they have no quirk at all...

He scribbles a few notes about how Puppy could counter the hero's quirk, imagining his quirk morphing into its dog form and running underneath the hero Backdraft's water gun attack. Water doesn't seem to impact Puppy like the cold does, he wonders if his quirk knows how to swim? Maybe they'll be able to test it today.

"Honey? Come get dressed, otherwise we won't be able to go to the beach for your birthday." Inko calls out, watching in amusement as Izuku hastily writes, tongue sticking out in concentration.

The boy shoots up like a rocket, quickly hauling Puppy off the ground and hoisting the crimson creature underneath his arm. He runs to get dressed, pulling on a limited edition All Might tee and his board shorts. The red sludge shifts into the form of a dog, its nubby feet more developed this time, with sharp claws on the ends of each toe, a patchy darker substance slowly starting to grow over its feet like sooty socks. Izuku thinks it might be fur, it's soft and velvety, like brand new skin, although it's still wet with the usual fluid that covers Puppy's fleshy body. Maybe when it dries out some fur will grow? Izuku can't wait! It's so exciting to see Puppy change and development, steadily getting bigger and stronger because of him. Izuku cares for it as much as it cares for him. He cleans it in the bath and cuddles it when it's cold, feeds it as often as his mother allows and soothes it when it's agitated. They go everywhere together, do everything together. He couldn't imagine living without Puppy.

Izuku stumbles out of his room in his beach clothes, hugging the crimson canine to his chest, its legs dangling over his arms, split mouth open and panting just like a 'real dog'. Inko shudders at the sight of it, but the sunhat her son has placed on its head does look kind of cute, in a morbid way.

The Beach isn't quite what they were expecting when they got there, a sizable pile of rubbish starting to build up on the end of it near the damaged pier. Litter scatters the sand and some bits of it even float in the water as it crashes against the rocks.

"Oh dear..." Inko frets, she didn't realise how trashy Dagobah beach had become. Perhaps they should go home and do something else for Izuku’s 8th birthday.

"How could people litter this much!" Izuku gasps. He holds Puppy up above his head, the crimson slime wriggling a bit, but still calm and content in his arms. "We should clean the beach!"

Izuku runs off squealing and giggling as Puppy's little legs kick in the air, trying to run alongside Izuku in his hold. Her sweet baby boy starts picking up soda bottles and plastic bits of rubbish. She manages to find a folded up plastic grocery bag in her purse for him to fill up and Izuku spends the next half an hour collecting litter just because he can. Dagobah beach doesn't really look any nicer, despite his efforts, but it's the thought that counts. Her precious baby is so sweet, always willing to help as much as he can.

The crimson creature slinks through the sand, shifting into its sludge form and slithering like a snake to the shore line. Izuku chases after it, having long since discarded his t-shirt in the summer heat, giggling and sweet. They splash around in the surf, the creature morphing again into an approximation of a dog and chasing the receding tide.

It's so strange to watch them play, she can't imagine something so disgusting and frightening actually having fun. It looks like something out of a horror movie, and yet it plays along with the facade of normalcy. She watches it, shaking its body, tentacles whipping side to side as Izuku continues to splash it with water, the little boy laughing every time he manages to soak it.

"Look mummy!" Izuku points, smiling wide, the bag of rubbish still looped through one of his arms. "Puppy is swimming!"

It certainly is... Inko watches in dismay as it twists and writhes, amorphous body splashing through the shallow water like a sea anemone, awkwardly propelling itself forward with a side to side motion. Izuku claps his hands in excitement, he didn't know if Puppy was capable of swimming, he's ecstatic, even if Puppy swims very poorly.

He happily reaches out for the slimy crimson thing when it starts to tire, floating like a rotting corpse in the water. It drips wet and limp when he picks it up, Izuku's fingers sinking into its sludge-like body, slim red tentacles curling around his forearms. Even from here she can see the faint bruising and red scabs littering his neck and chest, some even peeking down his back and trailing across his arms. The sight of them makes her feel like a failure, but she's doing everything she can, as far as she knows, Izuku is only feeding it every two days, but what if it's drinking from him at night? The doctors recorded some kind of chemical filled spit from its 'mouth' during their last visit, similar to a vampire bat's bite. They don't know exactly what it does, but it's likely some kind of anaesthetic or anti-coagulant. Inko shudders at the thought, the more they learn the more apparent it is that his quirk really is a parasite, that it doesn't seem to benefit him in any way the doctors can observe, just a mindless beast sapping away the vitality of her precious baby boy.

Izuku holds it close, swaying side to side happily as he gazes out at the clear summer day, a few white fluffy clouds making it look picture perfect. He bumps away a bit of floating trash, wading back to the shore with his quirk in his arms. Idly, Izuku realises that he isn't really having a birthday party, not like how it was before his quirk manifested, when Kacchan was still nice to him. He's gotten used to being alone, other kids just don't understand him, they think he's too loud and too weird, and his quirk just makes him creepy.

"Izuku honey, I think it's time to head home," Inko calls out. Izuku groans, slowly making his way back up the litter covered beach, Puppy dangling from his arms, all limp and relaxed, salty water dripping across the dry sand. Inko towels him dry, rubbing his soaking wet curly hair and making him whine in protest.

"What about Puppy, mummy?" Izuku softly asks, holding out his soaking wet quirk. It pulses idly, calm and content, limp tendrils draped over her baby's hands. "It's all wet."

In that moment, Inko wants to leave it here. Let it shrivel up and die for all she cares, Izuku is better off quirkless. It's just a parasite. A monster, clinging to her sweet innocent son.

She takes a deep breath to calm herself. It's alright, it's okay, she thinks. Inko wordlessly wipes down the slimy red thing, patting dry its tentacles and staying as calm as she can when it stretches open its terrifying mouth in a yawn, little fangs lining the inside of its throat like a living blender. Her towel is all slimy and wet now, she’ll have to bin it, thick crimson ooze covering it, a tacky line of slime connecting the fuzzy towel to the creature in her child's arms.

"Let's go home, Izuku."

--

"Mmwah!" Izuku makes an exaggerated sound as he plants a cute little kiss on the top of Puppy's head, the dog shaped sludge pants happily, splitting its mouth open to hang out its tentacle tongue. It's tail wags happily, a bit less stubby and strange looking than when it first took this form.

"Izuku!" Inko chastises from the driver's seat. "Don't kiss it!"

"Why not?" The little boy responds from the backseat, tapping his shoes together just because he can. He likes the sensation, although his teachers always tell him off during class for wriggling too much.

"It's not clean," Inko protests with all the certainty of an adult telling a child what to do.

"...But we have baths together," Izuku complains half-heartedly. Has he been doing it wrong this whole time? Puppy loves it when he kisses it, hugs it, shows it any kind of affection. And he loves when Puppy squeezes him tight, it's pulsing form wriggling in close at night, and soothing him with mindless chittering and gurgling when he's all mopey and sad after being left out of games at school.

Is it bad to kiss Puppy?

The slimy red quirk squirms between his hands, feeling his distress and nuzzling in closer, tendrils creeping across his lap possessively.

"Just- please Izuku, not in public," she says.

But they're not in public, they're in the car? Izuku doesn't understand, but he doesn't question it. Puppy slivers back under his clothes, wrapping around him like a full body backpack, red slime spread out across his torso, tendrils curling smoothly around his thighs and upper arms. Usually too much sensation like this would drive Izuku mad, but he likes the way Puppy holds him. He remembers the time when mum forgot to cut off the tags on the back of his new shirt and he was upset all day, itching the back of his neck until at the end of the day he was allowed to take it off and throw it into the back of his closet, hopefully to never be worn again.

Today they're going to yet another doctor's visit. The crook of his elbow still hurts from the last time they took some blood, but his mother insists. She's constantly stressing about his health, his appearance, worried that he's looking pale or thin or in some way sickly. The hospital also smells gross, it's too bright and it's boring and he's too old to play in the kiddie area with all the baby hero toys. He only plays with cool looking hero figurines. Puppy doesn't like the hospital either. They keep coming up with new tests to try out on his quirk, drawing blood, exposing it to high concentrations of particular chemicals, removing small portions for biopsies. But there's never anything wrong, he's not sick! They just want an excuse to not like Puppy, to tell his mummy that his quirk isn't good for him, that it's hurting him- and it kinda is- but it's to make Puppy strong!

"Well, Midoriya san, your son still has mild anaemia. Is he taking his supplements every day?" Yes, he hates them too.

"Yes doctor, I make sure he has them during breakfast," his mother says, winding her hands together anxiously.

"It shouldn't affect him too much, perhaps we could revisit in six months and see if there's any improvement?" His newest doctor proposes. Izuku fidgets in the corner with Puppy on his lap, his quirk agitated, slimy surface rippling at the sight of yet another white coated physician.

"Are you sure? You ran his blood again?"

"Yes Midoriya san, Izuku is doing fine, there's nothing we can do about his quirk until it develops further. This might just be Izuku’s life now, he'll likely have to learn to live with quirk diet supplements and some occasional light-headedness."

His mother doesn't look pleased by the news, but she doesn't press, thanking the doctor profusely and booking that six month appointment at the front desk just to settle her nerves.

They go home quieter than usual. Izuku doesn't really have the energy to talk to his mum, the doctors visit making him all tired now that the stressful part of it is finished.

Chapter Text

Izuku claps excitedly at the sight of several colourful fish swimming past the enormous aquarium glass. He tugs on his mother's sweater, pointing out all the different creatures as they pass by. A few small reef sharks and huge catfish, stingrays, turtles, sea horses. Izuku's mumbling goes a mile a minute, but Inko doesn't mind, it's endearing to watch her son be so excited. Pointing and gasping, and even scribbling down a list of sea creatures to sketch later on a spare scrap of paper.

He shoves the paper into the pocket of his hoodie. And it's all so happy and amazing that Inko nearly forgets the scabbed over split lip he has until Izuku turns around, having spent at least a minute pointing out every sea anemone in the tank. She feels her heart freeze for a moment, before it all trickles back in. The noise, the crowds, the dim ocean wave lights. Izuku has a brand new pair of noise cancelling headphones around his neck, just in case it gets a bit too loud, and Inko's so glad she picked them up on a whim for his last birthday.

She sighs, forcing a smile on her face as she nods along to her son's rambling. She can't stop looking at his split lip, the angry red scab, her gut twists. His disgusting little quirk makes an appearance, a curious little tentacle reaching out from the collar of Izuku’s hoodie, pointing to the fish just like its host and making Izuku laugh.

Why couldn't they have just left it at home, Just this once?

She tries to ignore it, but when they get to the coastal water tanks, Izuku lets it slither out between his hands to look. He shows it all the little sea stars and crabs, holding it just over the water, Puppy's tendrils tapping the surface hesitantly, curious and searching. Her son rambles about the octopus hiding in the corner, comparing it to his own quirk's tentacle abilities, and marvelling at all the fun facts he's memorised about cephalopods.

"Ma'am, quirk use is not allowed at the Aquarium." A staff member cuts in, sternly glaring at Izuku, his quirk hastily retracting in response.

"It's a sentient quirk." She explains. "I'm so sorry, he can't control it." Inko flushes, embarrassed at having been called out by the staff. A few passers-by stop and stare, watching the interaction, the humiliation.

Izuku mumbles a sorry too, "Puppy just wanted to look..." he says. And the staff member looks half disgusted at the fleshy red sludge the child's holding, no doubt unimpressed by Izuku’s less than accurate name for the squishy blob.

Inko bows profusely in apology before pulling her son away to another exhibit, wondering if they should just get lunch now and go home. But it's never that easy.

"Look, mummy!" Izuku holds up Puppy, the crimson sludge having taken the shape of a small squid-like creature.

"Puppy turned into a cep-cephalopod!" He cheers. His quirk's slimy red tentacles are lined with suckers like an octopus, its mantle thin and arrow shaped, clearly influenced by the exhibit's variety of captive squid and cuttlefish. It doesn't have eyes, just a fleshy red body, a thick vein running up the side of its body. The creature chitters, flaring its tentacles to reveal a horrid mouth in the centre where a squid's beak would be, sharp needle-like teeth spiralling down the inside of its throat.

"Honey-"

"Isn't it cool!" Her son doesn't seem to notice her distress, holding the slimy red squid in between his hands and marvelling at the complexity of Puppy's transformation. The syphon, the mantle, the combination of octopus and squid tentacles, the crimson creature trying its best to copy the animals in the exhibit, its squirming limbs dangling down, long enough to touch the floor.

She realises just how big the creature has gotten. It's so often hidden away beneath her son's clothes, an insidious parasite lurking just out of sight. But really it's the movement that's always freaked her out, the constant pulsing and squirming, like a bucket of worms or a vivisected heart.

A baby starts crying, people whispering and pointing, other kids looking scared. Inko begins to get nervous when two more staff members start speed walking towards them.

"Quirk use is strictly prohibited here, weren't you already given a warning?" And it all goes downhill from there.

"P-Puppy isn't hurting any-anyone, Sir," Izuku stammers out, looking stressed as they're confronted by the staff again, Puppy's tendrils curling around his arms, trying to sooth its host's rising heart rate.

"Izuku... I think it's best if you put your quirk away."

"But mum!-"

"She's right, kid. It's against the rules, now come on. You're scaring the other visitors. I'm afraid you'll have to leave, or we'll be forced to call the police."

Security escorts them out of the building, a tall scary looking man grabs her son by the top of his arm, tugging him and his grotesque quirk out the front door. Puppy is confiscated and held upside down by its tentacles by the other guard, a firm gloved hand squeezing it too tight, the slimy red creature hissing as it squirms, upset by the careless manhandling. Inko has never been so embarrassed before in her life, the shame, the humiliation. Izuku’s crying but she can't bring herself to comfort him as they leave the premises, she's just glad that filthy red slug hasn't bitten anyone yet.

Inko is disappointed. She doesn't say anything, not directly. But the new rule she sets in place speaks for itself.

"I'm sorry, Izuku," she's not. "But I don't think you can bring Puppy with you next time... You’ll just have to leave it at home during the day?"

Izuku hums noncommittally, not wanting to start an argument about it. He's feeling dejected and embarrassed, having gotten him and his mother kicked out because he couldn't ignore Puppy. Couldn't keep a lid on his quirk (that's just as active and curious as him), couldn't sit still, couldn't be normal. And it all comes swirling back to that. He's not normal, and neither is Puppy. He's starting to realise that more and more, the crushing weight of loneliness, of being rejected, excluded, ridiculed. If he's not being ignored he's being left behind, or worse, he's the weirdo, the free punching bag, quirk practice, for those better and more socially accepted than he'll ever be.

He knows Puppy is amazing! Just from watching and listening and learning it figured out how to create a whole new form. An extension of its animal copying mimicry that would be perfect for water rescue scenarios. He's disappointed yet again that nobody can see it from his perspective, that they'll only ever see Puppy's unsightly exterior and immediately hate it, hate them. Izuku finds himself tiring, having long since grown accustomed to this inevitable way of life. He finds himself filled with doubt, hugging Puppy's new amazing squid form close, those long tentacles tangling with his limbs, suckers playing with his clothes. They'll just have to become heroes together and prove everyone wrong…

--

They find him during lunch, sitting beneath a tree at the quiet end of the playground. Puppy is playing in his lap, Izuku wagging his fingers at it and giggling when it reaches out a tendril to grab him, trying to hold his fingers still to no avail. Although his quirk isn't really trying that hard, it feels more like a kitten batting at a piece of string.

"Oi! Deku!" Kacchan approaches him with a pack of goons. Tsubasa is holding a shoe box, a roll of tape shoved down the front pocket of his shorts.

"What's a villain like you even doing here, I can't believe they still let you in the school." Kacchan huffs, arms crossed, trying his best to look intimidating and scary despite being only nine years old.

The little green haired boy gulps, anxiously curling his arms around Puppy.

It's possibly the worst day of his life after that.

The group of boys manage to separate him and Puppy, cramming his writhing hissing red quirk in the shoe box and sealing it securely with as much tape as they can wrap around it. Izuku sobs and cries as loudly as he can, watching that box rattle and jolt, Puppy's fangs stabbing through the cardboard, only to be stepped on by another kid and bent the wrong way. They hold Izuku back as they kick the box back and forth between them, laughing smugly as the slimy creature slowly stops moving, retracting its fangs and pulling its aching body into itself.

It's not the first time they've hit him. Kacchan likes to practise his quirk on him, scaring his skin with little sun burst patterns. But it's the first time they've separated him from his quirk. They take turns punching him in the stomach, seeing how hard the group of boys can hit and laughing when he spits out foamy white vomit.

"Crybaby!" They jeer. "Spastic," another spits and it makes Kacchan laugh the most.

Puppy hisses weakly as they beat him up, the scent of its host blood spilling on the grass making it spasm, tendrils searching the edges of the box for any kind of escape. It feels like hours later when they leave Izuku crumpled up and crying on the floor, his lip swollen and split. He's sure they'll be a dozen bruises after this, littering his torso, aching and dark.

The bell rings but he ignores it, just cries and cries and eventually picks himself up, crawling over to the mangled taped up box Puppy is still trapped inside. It takes too long to open, his fingers still hurting from when someone stepped on them, his back aching where he was kicked several times trying to curl up into a ball and protect his head.

Eventually he rips the cardboard box open, but Puppy doesn't move much. Its body is a dull dark red, curled into a ball, a few little tendrils limply clinging to the sides. When Izuku sees the blood he starts freaking out. Tacky red liquid has soaked through the bottom of the box, Puppy bleeding sluggishly where it had been kicked too many times. The sight makes him start hyperventilating, sobbing all over again and shakily scooping up his precious quirk.

He doesn't go back to class. Doesn't go to the nurse's office. He just starts walking home, clutching Puppy's wet bleeding body close as he limps down the street. Mum won't be home yet, but Izuku knows where the spare key is. He lets himself in, locks himself in his room and breaks down with Puppy's wounded body in his arms. His quirk tries to comfort him, little red tendrils reaching across his shoulders and neck, but Izuku can't process it.

He rocks back and forth, screaming and crying, one hand unconsciously hitting the side of his head, not really noticing the pain with how much his whole body aches.

Why can't they leave him alone. Why did they have to hurt Puppy too!

The thought of going to school tomorrow fills him with an unfathomable dread, a sinking feeling in his guts that sucks all his energy down with it. He presses a kiss to the top of Puppy's form.

"I'm sorry... I'm sorry." Izuku begs for forgiveness, voice cracked and whiny, devastated that it's his fault Puppy got hurt. That he couldn't protect either of them.

Chapter Text

Midoriya Izuku is a scrawny little eleven year old. He's shorter than his classmates, he weighs less than them. He's also a picky eater, so Inko struggles to find foods he'll actually eat. She blames it on his parasitic quirk, certain that it's affecting his appetite, although there isn't much medical evidence to prove this. The freckles dotting his face only make his pale appearance all the more noticeable, and his often lumpy dishevelled school clothes don't help him look better. The little boy always lags behind during physical education, he's the last to be picked for team sports and he always hides away in the shower changing stalls rather than changing uniforms with the rest of the boys, scared that they'll laugh at his bite marks, scared that they'll pick on Puppy...

He comes home from school everyday with a headache. It's too loud and noisy in the classrooms, it's all too easy to get so overwhelmed that he feels like crying. School is a hostile place for Izuku, it feels like everyone is picking on him and the teachers always ignore him, or worse, they blame him for disturbing the class. He still dreads the locked box his teacher has under his desk, but Puppy hates it more. His quirk despises the confined space, always trembling and hissing whenever Izuku’s messes up and it's confiscated during class.

Ever since the boys at school have started beating him up, Puppy has gotten more and more aggressive towards new people. It spits and hisses whenever someone gets too close to its personal space, fangs flashing as it stretches its mouth in a snarl. He tries to soothe it, to calm the feisty red slime down, but he always feels calmer, safer, whenever people back up and give them both a bit of space.

His quirk doesn't carry scars like he does, its damaged cells merely shrivelling up and sloughing off, the creature quickly replacing it with fresh blood and vibrant nutrients. It's something that he's noted extensively in his notebooks, he wonders just how fast its regenerative abilities are, but he's too terrified to test his hypothesis, since Puppy would have to be hurt first in order to heal...

He tries to protect his quirk, even going so far as to hide it in his backpack when the other boys are going to beat him up. Even though Puppy hates dark confined spaces, it's still better than watching it bleed and wheeze, fleshy red body all blotchy and bruised dark red.

Izuku stretches and yawns at his desk, his homework from today long since completed beside him, the table lamp casting the room in long shadows. ‘Hero notes for the future 10’ is laid out before him, a bit charred and well loved, but legible enough for him to re-read all the extensive hero notes he's scribbled in every available corner of space. His obsession for heroes hasn't budged a bit, if anything it's grown, the young boy often seen mumbling and writing in his ratty notebook.

He brushes away some eraser dust, smiling proudly down at the extensive drawing of his quirk's potential digestive system. It's likely he'll never really know exactly how it works, but it's always enjoyable to jot down a new theory, the tantalising goal of efficient feeding and maximum growth speed hanging just out of reach. If they want to be heroes together, Puppy is going to need to grow really big and strong to be the bulk to their hero duo. He’s gonna be in middle school next year! Before he knows it he’ll be a high school student, hopefully in the amazingly prestigious UA, the best hero school in the country! But UA only takes a messily forty or so hero student applicants out of tens of thousands...

"Puppy?" Izuku chirps as he gets up from his desk, his quirk emerging from beneath a pile of previously folded clothes that needed putting away.

"Hey! They're all messy now..." Izuku whines playfully, trying to fold a pair of shorts only for his quirk to ambush him, jumping into his hands and forcing all of his attention on its rippling form. A sharp toothed mouth stretches open in the centre of Puppy's body, its tendrils eagerly climbing up his arms.

"Yes, I know. It's been two days, you know what that means?" Izuku smiles, the crimson monster gurgling and snapping its teeth.

"Time to eat!"

He switches off his bedside lamp, plunging the room into darkness and pulling the covers up, the young boy rubbing his legs together like a cricket. He relaxes in bed, all snuggly and warm, Puppy slinking across his skin and settling heavily across his chest. He likes the weight, it makes him feel oddly good, relaxed in a way few things do.

Puppy is a bit rough tonight, fangs sinking into his skin hungrily, the parasite biting a tad higher than Izuku usually prefers. He takes a slow deep breath, the creature's tendrils curling around his torso and arms, spreading out over the bed as Puppy shudders and undulates, drinking long and deep until Izuku feels a bit light headed.

"Hey Puppy..." he sleepily says, big green eyes lidded and drooping, "slow down a bit..."

His quirk has been getting more and more hungry between feedings, almost like it's going through a growth spurt. But Izuku’s too anxious to break his mother's rules, strictly sticking to the schedule despite how agitated it makes Puppy.

When it finally detaches, mouth bloody and red as it licks his wounds shut, Izuku feels uncomfortably woozy, his head still spinning from the drop in blood pressure. Puppy is fat and full atop his chest, veins bulging and prominent, its wriggling tentacles spreading out further, excited by the recent feeding.

"Did you like that, Puppy?" Izuku asks, hugging his satisfied quirk closer. Puppy just pulses, lively and energetic, it stretches out to reach his face, long leech-like mouth hovering over his. Its lengthy tentacle tongue languidly extends, waving curiously through the air, until it brushes against his lips.

"Puppy?" He whispers in surprise, his quirk dragging its blood wet tongue over his closed lips in response. Tonight something different happens after their usual feeding.

Tonight Puppy kisses him.

Izuku freezes as the slimy red creature presses their mouths closer together. That persistent tentacle working its way past his shut lips to press against his tongue, rubbing against the little pink muscle as its mouth nudges closer and closer until their kissing like girlfriends and boyfriends do.

He doesn't know what to do. Just lies there as Puppy explores his mouth, the iron copper taste of his own blood smearing against his lips and flooding the inside his mouth. Eventually he closes his eyes, stiff body slowly relaxing under Puppy's gentle touch. The tentacle tongue presses further into his mouth, splitting his lips open wider as it coils around itself in his mouth, wriggling and undulating, and making his cheeks bulge.

He feels funny, small body oddly warm as Puppy takes its time licking every corner of his mouth, tentacle tongue laving over his teeth and curling around and around his tongue, undulating against it as Puppy pulses and ripples. It's only when the creature knocks the back of his throat that he makes a sound, hands pushing against the slimy thing in distress as it pokes and prods a bit too far towards the back of his tongue.

They finally part with a wet sound, Puppy's tongue slowly dragging out of his panting mouth, wet and slimy with slick saliva. Puppy chitters excitedly, tentacles writhing and wet, its viscous body covered in a thicker layer of slimy slick, pulsing a bit faster than before.

"Wha- what was that?" Izuku pants, trying to catch his breath now that his mouth isn't full of Puppy.

His quirk curls around him possessively, mouth returning to its amorphous body now that it isn't required. It seems to nuzzle against him, practically purring in pleasure. Izuku’s completely baffled. Maybe he should write about this in his notebook?

But, he didnt hate it, the little boy decides. It actually felt kinda good, once he got over the surprise.

He likes Puppy's kisses...

--

Despite Puppy's best efforts, nothing it can think of is calming Izuku down.

The little boy wails beneath the old plastic slide, face all red and puffy and wet. His right arm aches where Kacchan burnt him, stinging and red, the sleeve of his school uniform singed and blackened. He's overwhelmed and panicking. Hyperventilating, his sobbing breaths wheezy and sporadic. He hits the side of his head, squeezing his hair with the other hand and rocking a bit back and forth, unable to pull himself out of this spiral.

Puppy ripples and hisses in his lap, little filaments gently tapping against him, but Izuku can't focus on it. He feels like he's breaking. He can't deal with the bullying, the jeers, the social isolation. He's got Puppy, but guiltily, it doesn't feel like enough.

Why can't he just stop being so fucking weird.

Puppy's hissing peaks, shrill and threatening. Izuku hits himself harder-

But then someone grabs his arm.

Izuku jolts, Puppy wrapping a dozen tendrils around the stranger and squeezing as hard as it can. The man grunts, but doesn't let him go.

"Hey, don't hurt yourself." The man says, voice flat and deep.

Izuku looks up through blurry eyes, snot running down his nose, still barely breathing. The man has short scratchy stubble, stern black eyes and long black hair hanging loose around his shoulders.

"Take a deep breath, kid. In... hold it... and out," the stranger demonstrates, breathing in slowly, holding it for a few seconds and then letting it out again. It takes Izuku a while to get there, hiccuping and gasping, but eventually his chest stops feeling so tight, the uncontrollable stream of tears slowing to a more manageable soft crying and weak sniffling.

Puppy hasn't let go of the man at all, if anything it gets tighter, tentacles constricting tight enough to bruise. The crimson sludge stretches its mouth as wide as it can, pushing the needle-like inside of its throat outwards, curling inside out just to show off more of its frightening white fangs.

"This your quirk, kid?" The man lets his arm go once he's calmed down some. But Puppy hangs on, slimy wetness building up thick and heavy where its tendrils squeeze.

Izuku nods. His throat hurts too much to talk. He rubs his cheek messily with his other hand and the man's eyes are instantly drawn to the painful looking burn on the side of his forearm.

"Think you could let me go?" The stranger asks. Izuku tries harder to get his breathing under control, wrapping his arms around Puppy's agitated form and shushing it like one would an upset child.

Gradually those tentacles loosen, the creature slipping away from the man and curling closer to Izuku. All the sharp pointy fangs covering its upturned mouth sink back into fleshy red sludge as it curls into a docile ball again, a few slimy lines still connecting the boy and his quirk.

"G-Good Puppy..." Izuku says softly, the man eyeing him strangely. He seems to study him for a moment, careful black eyes calm and collected.

"It's pretty late," he says. It's past 8pm, it's very late, his mother is going to be so mad at him when he eventually crawls home. The dim street lights do their best to light up the city park, but it's still dark and scary. Izuku nods at that too, although he's pretty sure the man wasn't really asking him a question.

"You safe at home?"

"Y-yeah..." Izuku murmurs, voice shaky and weak.

"Did someone at school hurt you?" Izuku nods.

"You've got a pretty cool quirk right there," the man says and now Izuku knows he's lying. No one likes his quirk. He hugs Puppy closer, little delicate red filaments reaching out to probe his wet face. Izuku stares at the man, really stares. Taking in his rough appearance, the scruffy clothes, the large dark bags beneath his eyes.

"A-Are you homeless?" Izuku asks bluntly. The man's face is flat, but the slightest hint of a smile tugs at his lips.

"Go home kid." The man says.

Izuku's about to follow his advice, but then Puppy surprises him. His quirk has been particularly hostile towards new people lately, but right now it reaches out, a soft little tendril curling around a bit of the man's long black hair and tugging lightly.

Izuku can't help cracking a smile, the man even smiles too.

Chapter Text

Izuku has a problem.

He can't stop kissing Puppy. And not just a peck on the cheek kind of kissing. No, he can't breathe when he kisses Puppy, gets so light headed he swoons, a drooling, whimpering, sucking on Puppy's tongue kinda kissing.

The needle sharp fangs don't bother him either. If they're careful he doesn't get cut, but if he does, Puppy will just lick it until it's all better. His quirk kisses his neck too, laving over bite marks and blushing bruises, licking down to his collar bones and kissing all over his chest until he's squirming and gasping beneath the covers.

He only lets Puppy kiss him when they're all alone. Like when they're supposed to be sleeping at night or bathing in the shower. One time Puppy kissed him extra long in the one of the school gym shower stalls, and he took so long 'getting changed' that he got in trouble for being late...

He's starting middle school next year, only a couple months away. But Izuku only feels a kind of weak, muted dread at the very notion of going to a new school, a bigger school, a school where he'll undoubtedly be the weirdo loser villainous kid with the gross quirk. But when he's kissing Puppy it all feels better. His head is so dizzy he can't even think straight, let alone stress and worry about new changes and more inevitable bullying.

He decides his mother can't ever know. She won't understand, she'll just want to separate them more. It's already bad enough with the limited feeding schedule. Puppy seems to hate the waiting more and more lately. It’s hit a growth spurt at the same time as him, that slip into puberty making Puppy salivate with hunger more often, starving for every drop of blood that Izuku can give it. If it drank from him more regularly, he's certain Puppy would be healthier, grow faster and bigger. It might not even need to drink as much during one feeding if Izuku could let it have him more often, perhaps every twelve hours? And if Puppy keeps kissing him after gorging itself with his blood, well, Izuku isn't going to turn down those breathless needy make out sessions.

Izuku leans back against the wooden playground beam, sitting on the tanbark with his legs spread, Puppy resting between his thighs. They’re lurking around that shitty little park he likes to visit often, the one where that hobo man was really nice to them, the two of them hiding under their faded plastic slide like forbidden lovers. Puppy licks at his neck like a hungry dog, its wet red skin breathing beneath Izuku’s hands, the boy’s eyes fluttering shut as his parasite sinks its fangs beneath his skin.

“Slowly, Puppy…” Izuku strokes a hand down its back, quickly glancing around to make sure no one can see them beneath the slide.

He feels kinda fuzzy, but that isn’t new. He must be a freak, to feel good while being fed off by a bloodsucking monster. The red sludge adjusts itself, keeping the blood flowing, its mass shifting, pressing harder between his legs. Izuku sucks down a whine, holding Puppy tighter.

Eventually his quirk pulls its fangs out of his fragile neck, tentacle tongue laving over the puncture wounds long and slow. Izuku makes a weird bitten off sound as the feeling between his legs gets more intense, his school shorts straining as Puppy inadvertently rubs against his crotch, the sludge shifting with pent up excitement.

“Puppy…” Izuku whines, holding his quirk closer, pressing it harder against his hips. The crimson sludge undulates, rubbing against him more purposefully, surly that can’t be an accident? Puppy sucks on his neck until he moans, that tentacle tongue definitely teasing him now, there’s no way his quirk is just looking after his bite wound.

“Puppy, please.” Izuku whimpers, teary eyed and needy as he tugs the crimson sludge up, pressing his lips against it and melting beneath that wet red tongue when it kisses him back.

That night he almost gets in trouble for staying out too late again. But it’s so worth it for the way Puppy had shoved its tongue down his throat under the slide, the taste of his own blood mildly addicting when it comes with Puppy kisses.

They keep having all these moments where kisses feel like they should become something different, something more, but neither of them can work out where to go next. They just grind against each other, rubbing and touching and holding each other close. Puppy feels good in his mouth and that’s all Izuku can really think about.

Everyday at school he looks forward to going home, looks forward to kissing Puppy when they’re finally alone. They must be really bonding as quirk and quirk user, or something like that. He’s even written about it in one of his notebooks dedicated to his quirk Demon Blood. He’s made a few notes about how Puppy tastes, the muscle strength of its tentacle tongue, how kissing might be a way to encourage feeding. But what if his mum reads it? What if she finds out and thinks it's weird, and makes them stop! In the end he decides to just tear out those pages and rip them up, burying them amongst other rubbish just in case anyone accidentally finds it.

He doesn’t know if he can go back to not kissing Puppy anymore. He likes it too much…

And it almost ruins their first day at middle school.

The first day of a new school is always the most stressful. He doesn’t know where the classrooms are and he hasn’t met any of the new teachers yet. Sensei has already explained to him that he’s going to be handing over the locked box to the new teacher as a ‘disciplinary method’. He’s given the new teacher a detailed report of Izuku’s long history of class disturbances and school yard fights, and Izuku is already dreading their first meeting, clearly having already been set up to fail by his elementary homeroom teacher. The new teacher is going to hate him and Puppy before they’ve even had the chance to meet.

“Good morning class, you can call me Nakamura Sensei.” His new teacher announces.

“Why don’t we go around the class and everyone can introduce themselves with their name and quirk.” The man says. It’s a standard ice-breaker activity, boring even, for those coming from the same elementary school who already know each other.

Izuku looks around the classroom, disappointed to see Kacchan in the room, despite already knowing they’d most likely be in the same class together. Izuku sinks lower into his seat, hoping the floor will open up and swallow him before he has to talk out loud to the class. He runs through his lines in his head, over and over again, crossing his fingers that he won’t accidentally say anything stupid instead. Hello my name is Midoriya Izuku, and my quirk is called Demon Blood. Wow, he should really change the name of it on the quirk registry, Demon Blood is such a scary name for Puppy.

“Next we have Midoriya?” The teacher interrupts his thoughts.

Izuku stands up hastily, brushing down his clothes nervously and stuttering out a hi.

“M-my name is… Midoriya I-Izuku! And- uh… My q-quirk is called D-Demon Blood- but- well that’s- It’s not very accurate, Puppy is such a sweetie! I don’t think it’s that scary.” He tries weakly to justify.

Bakugo barks out a short laugh. “That disgusting monster isn’t even close to being cute. You can’t be that delusional, Deku.”

“Well- I”

“Perhaps a demonstration?” The teacher unhelpfully asks, and this is the moment Izuku’s been dreading. Everyone in the class is going to laugh at him and be mean to Puppy…

“Um, okay… It might look a little scary, but he’s never bitten other people.” Izuku holds out his hands, coaxing Puppy to emerge from beneath his school uniform.

One girl screams at the sight of it, some of them recoiling in disgust, a few nervously talking to their friends, wondering what the hell kind of quirk is sitting in Midoriya’s hands. He’ll admit, Puppy isn’t the most… conventionally attractive, his slimy red quirk pulsing softly in his hands, tendrils draped over his arms, a vein bulging up the side of it as it wriggles and adjusts. The parasite isn’t as small as it used to be, it can’t really fit in his hands anymore, the majority of Puppy’s body is still tucked close to his chest, tendrils wrapped around his delicate body, almost protectively.

“Fuck sake Deku, has it gotten bigger!” Kacchan spits, cringing at the sight of it, vibrant and squirming before him.

“Well… yes, by about 500 grams since the last visit to the doctor. My mum likes to keep an eye on my quirk to see if there’s any adverse effects.” Izuku admits. He feels like that’s not what Kacchan meant, but he’s not really sure what response the other boy wanted.

“Puppy can turn my blood into body mass, and it even has several animal mimicking abilities! We’ve been trying to figure out a new form, but Puppy isn’t quite big enough yet, and it struggles creating bone mass, since there isn’t a lot of opportunity for calcium exchange…” Izuku trails off as he realises that the whole class is staring at him. The boy quickly bows and sits down, nervously pulling Puppy closer to his body and flushing bright pink when the stares persist.

“Gross,” a classmate says the next desk over. Izuku ducks his head.

“I’ve been told that Midoriya’s quirk is classified as a sentient parasitic quirk. It may also need to be confiscated during class if it proves to be too much of a distraction.” The teacher explains, the emphasis on parasitic letting Izuku know that this school year will be just as bad as every year before it.

There’s something about a parasite that creeps people out, the sentience aspect not doing any favours for it either. It feels like an alien lurking in the dark, waiting to take over the world and eat anyone it can get its jaws around. Izuku knows Puppy would never do anything like that, right? Regardless, Izuku settles in to have an abysmal first day at school, already regretting setting foot in the school as the teacher proceeds to ignore him everytime he puts his hand up.

--

That week he’s rostered on for cleaning duty afterschool on Friday. Homeroom class has to be spotless for Monday, he has to sweep the floors, wipe down the whiteboard, empty the bins and clean the desks, among other tasks. It’s just Izuku by himself today since everyone else refused to be paired up with him, claiming that his quirk scared them or they felt threatened by it. His new Sensei agreed with them and so Izuku resigned himself to taking twice as long cleaning, since he wouldn’t be getting any help.

He sends a quick text to his mum letting her know that he’s going to be home late. She sends a thumbs up back, so he pockets his phone and gets to work.

Cleaning is incredibly boring. Even with Puppy trailing behind him, little stubby dog tail wagging behind it, Izuku still finds himself staring off into space and contemplating dropping out of school entirely. His quirk tries to bark, a short yappy growl that comes out more like someone clearing their throat than any sound a real dog would make. He looks back at his quirk whilst tying up the bin bag, blinking curiously as Puppy pants beside him, long tentacle tongue hanging out.

“What is it, Puppy?” Izuku asks curiously, sitting down with his legs splayed out, the crimson sludge creature happily trotting forward and plonking itself in his lap like it belongs there. Puppy’s canine form is much larger than before, closer to a medium to large sized dog now. Its weight is getting pretty heavy to carry around, although his quirk is still much lighter than it should be for its mass. He’s got a few theories scribbled in his notebooks about density and mass relocation, that it might be using moisture from the air to rehydrate cells or something like that. It sounds kinda far out there, so he’s probably wrong, but it doesn’t hurt to wonder, to think and dream and come up with all sorts of crazy ideas that might one day help him take down a villain’s quirk and save the day with a smile.

But he’s jolted out of his thoughts by Puppy jumping up on his chest, its dark red paws a bit heavier and thicker than last time, little white nails dotting the tip of each toe. The monstrous dog splits its mouth in two, jaws cracking all the way down to its throat as it peels open, its fang filled tube-like mouth lingering by his face, drool dripping down onto the collar of his uniform.

“Hey, come on Puppy, we agreed to no feeding during school.” Izuku firmly reminds his quirk. The canine’s tentacle tongue extends out of its fang filled mouth, reaching out and nudging against his lips, pressing and pressing. Izuku raises his hands to push Puppy away, but it slips past his lips anyway, that filthy wet tongue wriggling into his mouth and sliding against his tongue.

He pulls Puppy closer, holds the parasite steady as it squirms and tastes and makes him see stars, little tendrils reaching out from its horrifying mouth to gently touch and feel. He’s so lost in the feeling of Puppy in his lap, in his mouth, that he doesn’t even notice the door open.

“Midoriya, I’ve just got to grab some papers-”

Izuku jolts away from Puppy with a spluttering cough, too much tentacle sliding out of his mouth as he looks towards his middle school homeroom teacher like a deer caught in the headlights. He tries a passive shaky smile, but his face is stuck blushing a mortified shade of red. Puppy continues to be unhelpful, persistently licking at his neck, crimson sludge rippling as it presses itself closer.

“What the hell are you doing?!” Nakamura Sensei immediately scowles at him. He has a look on his face that Izuku hasn’t really seen before, he’s never been in this much trouble before. All at once the possible consequences of his actions come rushing in, filling his insides with liquid anxiety as he sputters and protests, weakly standing with his quirk still in his arms to beg before his new Sensei.

“Please! Please don’t tell my mum.” Izuku begs, bowing as low as he can from where he’s standing. “She can’t know. I’m so sorry Sensei, it’ll never happen again-”

“Midoriya.” The teacher interrupts.

“Uh, yes?”

“Were you kissing your quirk? That is highly inappropriate. I should report you to the authorities for quirk misconduct.” The man threatens and Izuku can’t help it. He starts to cry, blubbering and wailing as he struggles to get a coherent sentence out.

The teacher lets this go on for a few minutes before he cuts off the boy’s sobbing, holding up a hand and demanding silence.

“Since this is the first time you’ve misbehaved in my classroom.” The teacher begins, “I’m willing to let you off lightly. I won’t tell your mother, for now. But if this ever happens again, you’ll be in massive trouble young man.”

Izuku nods his head up and down frantically, wiping his eyes with the back of his hand and hugging Puppy a bit closer just to feel safe again. He’s so very grateful his mother won’t know, for at least a bit longer that is. If he could have it his way she’d never know.

“Every morning you’ll place your quirk in the lockbox, and every afternoon you can collect it after school.”

“But!-”

“No excuses. This is how it’s going to be for the next two weeks. Do you understand me?” Nakamura Sensei sternly orders him.

All Izuku can do is nod weakly. He can’t explain that Puppy hates small dark spaces, that it makes it scared and agitated. He can’t explain that being separated from Puppy gives him anxiety too, that he needs Puppy more than he needs air. But the teacher doesn’t listen, will never listen. Izuku is just another weirdo little kid with a scary quirk who’s destined to be a villain. He’s just lucky that Nakamura Sensei didn’t escalate this as far as he could have.

Izuku meekly excuses himself, gathering up his notebooks and bag and running home crying, trying his best not to trip as he stumbles his way through fears and regrets and an all crippling anxiety of facing the world without Puppy by his side.

Chapter Text

Puppy is just as curious as he is. Its creeping red tendrils are always touching and feeling, curious about the world its host stumbles his way through, feeding off Izuku’s excited energy and nerdy passion for knowledge and analysis. But right now Puppy is very curious about the porn site Izuku’s just accidentally stumbled across.

Izuku can't stop watching. After having clicked off immediately the first time he followed the fourth link of a search result for 'big strong heros', he quickly finds himself pressing it again, just to satisfy his curiosity.

It's a guy in a hawks costume bouncing on the cock of some muscular dude wearing a poorly crafted All Might wig. The man sitting in his lap moans and gasps, grinding away, spreading his cheeks lewdly just to show the camera how deep it is inside of him. Izuku's rock hard before he even really knows what's going on.

Mummy wouldn't want him looking at this stuff and he quickly turns down the volume until the little speaker has a line through it, mortified by the thought of his mother suddenly barging into his room. And so he hides under the bedsheets, bringing his little silver laptop with him and watching the strange new video all the way to the end.

'HAWKS X ALL MIGHT BIG COCK HERO' the title reads obnoxiously, he's terrified to click on anything else so he just watches the video again and again, repeating the last 30 seconds as it grips his brain and makes him feel all funny. At the end the fake All Might makes the Hawks guy all wet and sticky, something thick and white and runny coming out after Hawks lifts his rear up and bends over for the camera, pink furled hole twitching as it drips.

Izuku finds himself rubbing his legs together like a cricket, feeling good, little dick achy and weird.

It doesn't take long to figure out how to make it feel better, Puppy does it for him.

His quirk slips back underneath his clothes, little feeler tendrils tapping against his skin, exploring and touching and quickly finding his stiff little cock. Izuku startles at the grip on his dick, Puppy curling a tendril around the base, tiny filaments running along his shaft before all of Puppy converges between his legs, pushing down his pyjama shorts.

The video replays idly in the background, but Izuku can't focus on that, he's too busy trying to buck his hips into the achingly tight grip around his prick. The sticky crimson sludge engulfs the entirety of his private parts, tasting and touching, making him so much harder and wetter than he’s ever been. Little beads of runny precum leak out of the gummy pink head, Puppy drinking that down and even pushing a tiny thin filament tendril into the tip of his dick just to find more. The crimson creature squeezes around him in a way he's never been touched before, undulating, once, twice, trying to clumsily match the rhythm of the video, but Izuku’s already cumming, shooting his first tiny load of cum into Puppy's viscous crimson body.

His quirk prickles between his legs, body rippling as it processes the unique flavour of its host. Izuku feels drained, emotionally and physically. And it hurts a bit now to have Puppy still completely cover his dick, the red sludge pushing back his foreskin just to explore more of the tip. The little boy whimpers, tears beading at the corners of his eyelashes, always so quick to cry. He pushes at Puppy weakly, hoping his quick will get the message and thankfully it does, the veiny crimson sludge rippling a bit before carefully slipping away from his crotch, a few errant tendrils clinging to the base of his cock, his pudgy little balls and the soft bit of skin along his taint. Most of Puppy sits heavily on his chest, still curious about the flavour of his cum, the way his heartbeat peaked, the smell of arousal making the scent of Izuku’s blood all the sweeter.

After a few minutes to recover the young boy bookmarks the web page, committed to coming back here sooner rather than later, and having Puppy touch him again. Perhaps he'll touch himself too, maybe it will feel even better then!

He wants to write about it in his latest journal, but something tells him not to. What if his mum reads it! He thinks mortified again.

--

Izuku fidgets at his next quirk doctor's appointment. They take his blood again at the insistence of his mother, the procedure routine and boring by now. They never find anything different, but they keep looking anyway, forever vigilant for any sign that Puppy might be harmful to him.

He squirms on the cushioned patient bed, the crinkle of the plastic irritating him somewhat, although that doesn't stop him kicking his legs back and forth. He wonders if the doctor could figure out why Puppy makes him feel so good? He sort of wants to ask, but he's far too embarrassed with his mother in the room. She can't possibly know that he's been watching those kinds of videos. And letting Puppy kiss him. And feeling really really good when Puppy bites him and touches him like that. It's become somewhat of a guilty pleasure now, to search through Hero Red Tube for porn and wanking while Puppy kisses him, his quirk often biting down to drink right as he cums. Just the thought of it makes him a little flustered and he focuses really hard on the body health chart on the wall to clear his thoughts, Puppy's agitated squirming not helping in the least.

"Okay Midoriya, we're almost done." The nurse informs him, setting up the scale to weigh Puppy again, even though it's only been four months.

"Um…" Izuku turns to the doctor writing down notes on a chart. "I know… kids go through puberty." He starts, hesitant and small and Inko's head snaps to him, startled and confused. The doctor looks up patiently, waiting for his question.

"Is it… Is it possible… that Puppy might go through puberty too? I mean- I know it's just a quirk, but parasitic quirks seem to grow when sustained by their food of choice. If Puppy can grow, surely it has some kind of development cycle?..." Izuku trails off, realising that everyone is staring again, and ducking his head with a blush when it all becomes too much.

He hates doctor's appointments…

"Well Midoriya, that might be true, although I'm not sure what signs your quirk may exhibit that would indicate another stage of growth, have you noticed anything?"

"Um- Well-" Izuku glances at his worried mother, her hands already scrunching up the hem of her dress. He thinks about the kisses, the increased affection, Puppy's clinginess.

"No…" He finishes lamely, frustrated that he couldn't get himself to ask the questions he really wanted to.

What if Puppy is growing up faster than him? He was fine with kisses and hugs, but Puppy always wants to go further, wants to touch and feel and taste. He can't help but get sucked into the parasite's addictive affection no matter how nervous or unready he feels. They've been watching so much porn and finding tutorials and guides and… Puppy wants to go further, wants to make him feel amazing and he just doesn't know why? What quirk evolutionary gain does this have? Does it increase the bond between parasite and host? Does it encourage blood regeneration in the host or improve Puppy's digestive system? Or maybe… maybe Puppy just loves him that much. Just wants to be with him and care for him, because they're all they've ever had. It's been him and Puppy against the world for so long, he'd do anything for his quirk.

Izuku bites his tongue, shakes his head and the quirk checkup goes as usual, weighing, measuring, questioning, and he's free to go. He doesn't even know why they bother going anymore. None of the doctors are willing to run anymore tests and there's nothing new they could learn there. The last time he tried engaging with the clinic, he showed them Puppy's new squid form and they were less than impressed, advising he limit Puppy's feeding to prevent 'uncontrollable mutations'. Izuku sighs, what a waste of medical and scientific resources.

"Are you sure everything is alright?" His mother double checks again with the doctor, it's part of the routine at this point. When all the results come back fine, his mother just has to interrogate them, convinced they're missing some fatal disease caused by her child's unfortunate quirk.

"Well actually," the doctor speaks quietly, "if the parasite is going through puberty, it may have a unique hormonal system that we wouldn't be able to monitor. The creature's biology is entirely unique. It could suddenly have a growth spurt or enter some kind of alien reproductive stage. I'd keep a close eye on your son, just in case." He explains, just out of earshot of Izuku, the boy spinning in a circle in the hallway, bored out of his mind and more than ready to go home.

Chapter Text

"Kid." The homeless man from before calls out, tone flat and bored and Izuku looks up from where he'd been playing with Puppy, his quirk's crimson tendrils reaching from his lap to curl around his fingers. He'd been trying to teach Puppy to count, showing his quirk different numbers of fingers and cheering when Puppy stretches out the correct amount of tendrils to curl around him. But now Izuku’s attention is drawn away, big green eyes blown wide as he takes in the grumpy scruffy homeless looking man before him. The guy scratches his stubble, looking bored and plain as he subtly examines the child hiding once again under the green plastic slide.

The crimson blob hisses at him for stopping their game, its slimy body rippling as it grabs the front of Izuku’s scuffed up school clothes. His hands lower automatically to soothe Puppy, stroking and petting the slime until its agitation is assuaged. He does it without thinking, already feeling more relaxed with the lukewarm wetness beneath his touch. The man's eyes dart down to his quirk, an unreadable look in his gaze.

Izuku knows it's kind of late, the street lights have come on and he keeps getting texts and phone calls from his mum, but he just needs a minute to decompress, the pressure of school and medical tests and endless bullying draining what little energy he has left. They were just gonna make out a little and head home, but now that kind stranger is back. He knows he shouldn't talk to strangers, but he's got a burning curiosity. He can't help but wonder why he came back and what his quirk really is? And what's up with his scruffy clothes? Is he actually homeless?

"Hi." Izuku responds against his better judgement, ogling the man much less subtly. He takes in the strange white scarf, the nearly unnoticeable combat boots (likely reinforced with steel toes) and the hint of yellow plastic hidden around his neck. This guy sure dresses weird, maybe he's in a gang? Izuku mutters to himself all the little questions in his head, he's never been very good at staying quiet, but the man doesn't interrupt, just hides a smile in his scarf as the boy wonders if he's some kind of construction worker or a beggar on the streets.

"I see you're all roughed up again?" The man starts, pointedly looking at the bruise staining his cheek, an old scab on Izuku's lip proving he took a good hit to the face.

Izuku blushes and ducks his head, "yeah…" He doesn't really know what to say, it's not like this random stranger will care if he's being beaten up at school or not. The man isn't blind, surely he can see Puppy's disgusting form sitting in his lap and know whatever punishment he's suffering is well earned for having such a villainous quirk.

"Are you okay?"

"Mhm," Izuku dismisses with a nod, curling his fingers around Puppy and lifting it up, stretching out the crimson slime until it all drips back into his lap. Sometimes he plays with Puppy without thinking about it, like having a living breathing fidget toy on his person whenever his mind goes wool gathering and he struggles to hold onto conversations.

"Really?" The man questions. Izuku blushes, why is this guy so persistent?

"Yeah I'm fine, I've got Puppy with me."

"Then why are you out late again? Last time I saw you here… you weren't doing too good."

"I'm fine, really. Some of the kids are just a bit rough at school…" Izuku weakly explains, eyes focused on the red blob in his lap, the squishy pulsing thing reaching back, playfully tugging on his fingers to keep him entertained.

"I'm guessing they don't like your quirk?" The man looks away, easing up on the interrogation-like atmosphere. Izuku nods in his peripheral vision.

"They think it's scary…" Izuku adds. "Do you think it's scary, Mister?"

"Hmm? Nah. It takes a bit more than a red blob to scare me." The man jokes flatly.

"Hey! Puppy isn't just a blob!" Izuku is quick to defend, "it's amazing! Look!" Izuku holds up the creature. Puppy seamlessly shifts into its canine form, pulling on all the slime gathered in Izuku's lap and the parts of itself hidden beneath his clothes to form a medium sized dog-like creature. It wags its stubby tail, poorly fitting in Izuku's lap now and the man appraises the quirk with a new light, subconsciously analysing how he'd take it on in a fight.

"It's not an emitter quirk, right?"

"Nu-uh, it's a sentient quirk! Puppy is its own entity. We have a bond, obviously, since we've been together since it first manifested. But its existence doesn't seem to be directly linked to me. Well, it wouldn't have any food without me, but in theory it could find another host." Izuku explains, it's a bit of a mouthful, but the man seems to get the gist of it.

"It depends on you for food?"

"It's a parasitic quirk…"

"Ah I see." The man nods. And that's all he says, he doesn't pull a face or tell him that's gross, just accepts Izuku’s explanation.

They talk like that for a while, Izuku happily explaining the intricacies of his quirk to the man and relaxing with Puppy in his lap, petting the faux dog’s tummy, its tongue lolling out. The man eventually sits down across from him, knees creaking, his back resting on the supporting pole of a string of monkey bars, but he leaves plenty of space between them, making sure the kid doesn't feel boxed in or creeped out by him. He's an excitable little kid, full of energy and life and a well of quirk knowledge, his curiosity burning to no end when a new quirk is dangled before him.

"What do you think my quirk is?"

And doesn't that get the kid talking. He'd originally only wanted to check in on the boy, make sure he's alright and isn't afraid to go home or something, but instead he ends up talking to the kid for at least half an hour, maybe longer.

"You don't seem to have any obvious physical mutations, but I keep meeting you in the evenings, so maybe it's something relating to sleep? Or functions better during the night? You might have some kind of eye related quirk due to how sleepy and bloodshot your eyes look. Although, maybe that's just because you're homeless." He doesn't correct the kid on his guesses or assumptions, just lets the boy talk it all out, admiring his use of logical reasoning and evidence based hypothesis. He's kind of impressed, clearly the boy has some intelligence or at least a very strong obsession with quirks, although he could use some more confidence and could work on voicing his ideas more succinctly.

"Well, I've got to head off soon, and you should too. It's way too late for little kids to be wandering around outside on their own."

"I'm not that young…" Izuku complains, "and you never confirmed any of my guesses!" The boy whines, more upset over the withholding of valuable quirk knowledge than being told off by an adult.

"You never settled on one quirk, I can't have various forms of telekinesis and eyes that turn people to stone. Everyone only gets one quirk." The man smirks, tilting his head to bury it in his capture scarf.

"But- I- how can I know without seeing it in action!"

The man shrugs, "give me your best guess."

Izuku gapes, frustrated and conflicted as he struggles to answer the man.

"... Manipulating shadows!"

"Wrong."

"Arggghh!" Izuku complains loudly, Puppy rippling in amusement as its host grumbles and gripes, second guessing every quirk hypothesis and theory that crosses his mind.

"I knew that was too unlikely…"

The man stands up, holding out a hand to pull Izuku up too, Puppy stepping out of his lap to let the boy stand.

"The name's Aizawa Shouta." The man says, tone still flat and unreadable like it has been for nearly the whole conversation. Izuku feels like it's a bit lighter though, like maybe the man wasn't completely annoyed by having to sit and listen to him ramble about quirk's for god knows how long.

"Uh, Midoriya Izuku." He offers back and the man, Aizawa, nods, casually shoving his hands in his baggy pockets.

Standing up like this, Aizawa can see just how big 'Puppy' is. The sentient quirk is almost larger than a working dog, coming up well over the boy's hip on all fours. Although it's wiry and thin like a greyhound, visible bone white ribs poking through where crimson muscle and slime doesn't quite cover it. A darker red pigmentation covers its paws and reaches up to its elbows, a few stray fang-like spines and strands manifesting across its back like the beginnings of a nightmarish porcupine. It adjusts its jaws, mouth curling open to lick a tentacle tongue over previously hidden needle sharp fangs. Suddenly he's not so sure he could take the boy's quirk in a fight, but he does well to hide his unease at the sight of its strange vertical mouth. He keeps the conversation calm, scratching at his stubble like the boy's quirk isn't terrifying to behold. He refuses to make another kid feel bad about the quirk they were born with, there's nothing wrong with Puppy, it's his own human tendency to be scared of the unknown that makes Aizawa prickle with unease.

He reaches out a hand to Puppy. "Does it like pets?" He asks, checking that he's doing the right thing, that he isn't somehow demeaning the sentient quirk by treating it like an animal.

"Uh yeah! Puppy usually loves pets, although I've been the only one to pet it, so maybe it won't like strangers petting it?" Izuku frowns, not quite sure where Puppy's boundaries lie.

Aizawa slowly reaches out anyway, the creature warily eyeing him as he presses a hand to the top of Puppy's wet eyeless skull. He gingerly strokes the odd dog, hesitant at first, but then it wags its nubby tail, the beast's mouth creaking open to fake pant, its tentacle tongue lolling out casually.

"I think Puppy likes that!" Izuku translates in case the happy body language wasn't enough. Izuku was actually a little worried that his quirk might bite the man. If any of the kids at school had tried that, Puppy would have immediately torn into them, like that time Puppy ripped up his only Endeavour plush, those needle-like teeth tearing into fabric and spraying stuffing all over the floor. He's glad Puppy is being nice right now. It's been through so much, the other kids relentlessly teasing and agitating it, just to laugh when Puppy is rightfully upset.

The skinless crimson dog curls its tentacle tongue around Aizawa’s wrist, squeezing just so before releasing him. The man keeps his cool, letting his hand fall back to his side and resisting the urge to wipe off the wetness on the leg of his pants. It kind of felt like being pet back, in a weird way, like he’d just earned Puppy’s approval by being kind to its host. He’s probably overthinking things, but he hopes to see the two again some day, preferably without being covered in bruises and injuries or sobbing and crying in the middle of a breakdown. But that seems unlikely with the unfortunately frightening quirk Midoriya’s been saddled with. Kids used to bully him for his own villainous quirk and Erasure isn’t anywhere near as confronting and strange as Izuku’s quirk is.

“I’ll see you around, kid. Stay out of trouble.” Aizawa says, ruffling the top of the boy’s curly green hair.

“See ya, Mr. Aizawa.” Midoriya bows curtly. He holds his arms out towards Puppy and smiles when his quirk morphs back into liquid and leaps into his arms, crimson sludge hiding back underneath the boy’s torn up school uniform. It disappears out of sight surprisingly faster than Aizawa would have thought possible for its large size.

The kid runs off and Aizawa likes to think he’s a bit happier after that conversation, that maybe he feels a bit less alone.