"There shall not be found among you... one who inquires of Yid'oni"—Deuteronomy 18:10-11.
The Torah forbids us from consulting with a Yid'oni practitioner, to ask him for advice or information based on his Yid'oni experience.
The Yid'oni practice consisted of inserting into one's mouth a bone from the yidoa fowl. After then burning incense, saying certain formulas and doing certain rites, the person would enter a trance-like state, and he would begin issuing predictions about the future.