The Arm-Thrower Squid or Octopoteuthis Deletron seems somewhat typical of deep sea squid at first glance, but has recently demonstrated a unique and rather morbid defensive mechanism; when attacked, it can detach and release one or more of its hook-lined arms, which will reflexively wrap around whatever they touch and flash from red to white while the squid makes its escape.



Many other cephalopods can shed arms when attacked, but only deletron, as far as we know, has arms adapted to actually fight back while the rest of the animal flees. It’s called “attack autonomy,” and is known in only a handful of other animals, most notably in honeybees, whose stings continue to pump venom after tearing free from the body.