There is also a mental illness called lycanthropy in which a patient believes he or she is, or has transformed into, an animal and behaves accordingly. This is sometimes referred to as clinical lycanthropy to distinguish it from its use in legends. This name came from a gruesome Greek king named Lycaon.
The story of Lycaon the king explains how werewolves first came into the world. Lycaon was a very fierce and cruel king. His cruelty was legendary. When the powerful God, Zeus heard of his mischievous actions, he decided to come down to see for himself. To his surprise the truth was worse than what he had heard. Zeus went at once to meet with King Lycaon. When Zeus revealed himself at Lycaon's kingdom, Lycaon's servants got on their knees to pray. Lycaon however did not believe that Zeus was a god and made a plan to test him. Lycaon planned to kill him. If he was a god he would survive but if he wasn't then he would die. First he invited Zeus to a feast that he had prepared himself. The feast was human flesh from an innocent messenger that he had killed. Zeus, since he was a god knew at once what was happening and was furious with Lycaon’s cannibalism. As a punishment Zeus turned Lycaon into a wolf. Lycaon's entire body changed, only his eyes were human.