I first saw Mamá on YouTube back in 2013 and I can remember having trouble sleeping afterwards. This is atmospheric, scary and in your face. The images you see here will stay in your head no matter what. There's no going back after watching this. Three minutes is the perfect length for this little horror gem.
This is far greater than the feature that followed.
I have revisited it many times and when you know the outcome, the tension is palpable.
Highly recommended.
Tip: watch it late at night and alone under a blanket with the lights turned off.