Zombies

Zombies weren't created by George Romero, but he sure did popularize them. Like the monsters themselves, they have long been a part of popular culture, and our fascination with them just won't go away. Yet as it seems, they might be more than just sluggish walkers with a fanciful appetite for human flesh.

A person with Cotard Syndrome actually feels they are dead yet is still alive and well. Jules Cotard, the physician who made the initial diagnosis, characterizes it as a combination of depression, anxious melancholia, and delusions. Those who have it think they are dead and are hence unmotivated to achieve much with their lives. There is no need to work, eat, or do anything else. They genuinely think they've passed away.

This is a type of delusion, possibly brought on by a brain damage or another ailment. To understand the specific cause of the syndrome and why those who have it feel this way, however, very little research has been done.