The delusion that you have assumed the form of an animal

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
form of insanity in which a man imagines himself to be another type of beast, 1845, from French zoanthrope or directly from Modern Latin zoanthropia , from Greek zoion "animal" (see zoo ) + anthropos "man" (see anthropo- ).

Wiktionary Word definitions in Wiktionary
n. (context medicine English) A kind of delusion in which the patient believes himself transformed into one of the lower animals. http://archimedes.fas.harvard.edu/cgi-bin/dict?name=webster&lang=en&word=zoanthropy&

WordNet Word definitions in WordNet
n. the delusion that you have assumed the form of an animal

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Zoanthropy \Zo*an"thro*py\, n. [Gr. ? animal + ? man.] (Med.) A kind of monomania in which the patient believes himself transformed into one of the lower animals.