To not ask a yidaaoni: That we not ask a yidaaoni. And this matter is that the sorcerer puts a bone from an animal, the name of which is yidoaa, into his mouth, and that bone speaks through magic. And [regarding] this animal, the name of which is yidoaa, I have seen in a book from the Geonim (early post-Talmudic authorities) that (see Rash on Mishnah Kilayim 8:5) it grows with a large cord that comes out of the ground, similar to the cord of squash and pumpkins, its form is like the form of a man in everything - in the face, the body, the hands and the feet - and it is connected to the cord from its navel. And no creature can approach for the cord's length, since it grazes around it like the length of the cord, and it devours all that it can reach. And when they come to hunt it, they shoot arrows into its cord, until it is separated, and [then] it dies immediately. And in Talmud Yerushalmi Kilayim 8:4, they, may their memory be blessed, said in explanation of "For your covenant will be with the rocks of the field" (Job 5:23), "It is a man of the mountain, and it lives from its navel. If its navel is separated, it does not live."
The root of this commandment and all of its content - regarding its laws and its obligation - is like the content of the commandment of ov that we wrote adjacently (Sefer HaChinukh 513).