Rabbi Nachman told the story of how a king's son became mad. He imagined that he was a turkey, and that he had to sit naked under the table and scratch around amongst the pieces of old bones and breadcrumbs. All the doctors in the realm despaired of being able to help him or cure him, and the king was very sad. Eventually a wise man came and said that he would undertake to cure him. He too stripped himself naked, sat under the table next to the king's son and began to scratch among the breadcrumbs and the bonemeal.
The king's son asked him who he was and what he was doing there. The wise man replied, I am a turkey. What are you doing here? I too am a turkey, said the king's son. So they sat there together for some time until they became used to one another. Then the wise man indicated that some shirts should be thrown to him, and he said to the king's son: Do you assume that a turkey cannot wear a shirt? He most certainly can wear a shirt and remain a turkey. So they both put on shirts. A little while later the wise man indicated that they should throw him some trousers, and as before he said: Do you think that just because someone is wearing trousers he cannot be a turkey? So they both put on trousers. It went on like this until they were both fully dressed. The wise man then indicated that they should throw them down some human food from the table, and he said to the king's son: Do you think that just because someone eats good food they cannot be a turkey? One most certainly can. So they both ate together. After that he said to him: Do you think a turkey has to eat under the table? It is possible to be a turkey and eat at the table itself. In this way the wise man continued until he had completely healed him.
-from The Wisdom of the Jewish Mystics