Jikininki

In Zen Buddhism, jikininki are some of the ugliest demons imaginable and represent anything that has to do with greed and selfishness. Their favorite hobby appears to be the nightly consumption of human corpses since rotting human flesh is to a jikininki what pizza is to a human. For that matter, their bad nutrition seems to be the main reason why they look more like zombies rather than your typical demon or evil spirit. However, they do possess the ability to look like humans when they want to deceive and corrupt someone. Nevertheless, when they are in their ordinary form they are so ghastly and horrifying to look at that if any mortal has the bad luck to see one, the fright might give them amnesia.