Demonoids look like humans, but well, eyes that are longer and almost reaching the ears, which are like the ears of a vulcan... women heads are more squished and flat at the back. prosopometamorphopsia actually shows the appearance of this species, these aliens live on a world, like ours named Demonistan, located on a world far away. prosopometamorphopsia, otherwise known as "Demon Face Syndrome" shows us a glimpse at the species... people who has it (i believe, hear a schitzo out yo-) were formerly Demonoid, thus seeing these faces mean your brain is re-constructing faces to ones that remind you of your species despite you not remembering them, thus your horrified. i suggest you don't look it up unless you want to be horrified... the name of the species comes from the syndrome itself, which is genetic, although this is my (schizophrenic) explanation of why the faces look "not human"