Tractate Sanhedrin, Herbert Danby tr. , at sacred-texts.com
M.VII. 7b. The Ba‘al ‘Ob, 1 that is, the Python 2 who speaks from his armpits, and the Yidd‘oni 3 who speaks from his mouth, are punishable by stoning; and he who has inquired of them (offends) against an explicit warning. 4
7. HE WHO INQUIRES OF THE DEAD; 6---that is, one who conjures up the dead by witchcraft, or one who inquires of a skull. What is the difference between one who inquires of a skull and one who conjures up the dead by witchcraft? When one conjures up the dead by witchcraft it (the ghost) does not come up in the proper way, 7 nor will it come up on the Sabbath; but when one inquires of a skull it comes up in the ordinary way, and will also come up on the Sabbath.
101:1 Lev. 19. 31; 20. 27; Deut. 18. 11.
101:2 Vulgate of Lev. 20. 27. "Vir sive mulier in quibus pythonicus . . . fuerit spiritus." LXX normally renders ‘Ob by ἐγγαστρίμυθοι, and Plutarch De defectu oraculorum, states that in his time ἐγγαστρίμυθοι were called πύθωνες. Cf. Acts 16. 16.
101:3 R. V. Deut. 18. 11: "familiar spirit."
101:4 Cf. Lev. 19. 31.
101:5 Sanh. 65b has yaddu‘a. This, according to Rashi, was a wild beast, or, according to Maimonides, a bird.
101:6 Deut. 18. 11.
101:7 That is, according to Rashi, feet uppermost.