"shoel av": a necromancer that projects speech from his armpits.
They themselves are liable to stoning, and those who consult them are in transgression of an exhortation. Whether he raises (a spirit) on his male member or consults a skull. What is the difference between the first and the second? When one raises (a spirit) on his male member, it does not rise naturally, and is not consulted on the Sabbath. When he consults a skull, it ascends naturally and is consulted on the Sabbath.
["and one who consults the dead": This is one who starves himself and goes and sleeps in the cemetery so that the spirit of tumah (uncleanliness) repose itself upon him. And when R. Akiva came to this verse, he said: "Woe unto us! If the spirit of tumah reposes upon one who cleaves to tumah, how much more so should the holy spirit repose upon one who cleaves to the Shechinah! What brought this (absence of the holy spirit) about? Your sins sundered you from your G-d!"]