Boanthropy

Boanthropy is a delusion in which a person believes themselves to be an ox or cow, generally treated by psychiatry as a form of clinical lycanthropy, the broader delusion of having transformed into an animal, and associated with conditions such as schizophrenia, psychotic depression, or bipolar disorder. The best known historical case attributed to it is the Book of Daniels account of the Babylonian king Nebuchadnezzar II being driven from his court and eating grass like cattle, and Persian sources describe a similar delusion in the Buyid prince Majd al-Dawla, who believed himself a cow and asked to be slaughtered, a case the physician Avicenna is credited with successfully treating.