146. Sorcery
Avodas Kochavim 6:1
If a person willingly and intentionally performs actions associated with various types of sorcery, he is liable for the penalty of excision (kareis). If there are witnesses who warned him, the offender is executed by stoning. If he did these things inadvertently, he must bring a sin offering.
One type of sorcerer is called an ov. He stands up and offers a particular offering of incense, waving a myrtle wand and whispering an incantation. He does this until the one consulting him (whom we’ll call “the client”) hears a voice, as if someone were speaking to him and answering his questions. The words seem to come from below the ground in a low tone so that they can’t be heard by the ear, just in the mind. Something else an ov does is take a human skull, offer incense and chant incantations until his client hears a voice emanating softly from the ov’s armpit, answering the client’s questions. One who performs such deeds is liable to stoning.
Avodas Kochavim 6:2
Another type of sorcerer is the yidoni. A yidoni places a bone from a bird called the yidua in his mouth. He offers incense and performs other rituals until he goes into a trance. He has a kind of seizure and relates events that will occur in the future.
All of these sorceries are forms of idolatry. The Torah prohibits them in Leviticus 19:31, “Do not turn to mediums or necromancers.”