Cotard Delusion is a rare, fascinating, and frightening disorder in which a person irrationally thinks they are dead, dying, or decomposing. In many cases, people will think that they do not fully exist or are immortal, in spite of their feelings of death.

Considered a delusion of negation, individuals suffering from Cotard Delusion will often deny that they are completely intact and will feel that parts of their body are missing. The delusion is typically related to depression, schizophrenia, and psychosis.