What does Paul mean by "witchcraft" in Galatians 5:20?

I recently came across this: > Gal 5:19 Now the works of the flesh are manifest, which are these; Adultery, fornication, uncleanness, lasciviousness, Gal 5:20 Idolatry, **witchcraft**, hatred, variance, emulations, wrath, strife, seditions, heresies, Gal 5:21 Envyings, murders, drunkenness, revellings, and such like: of the which I tell you before, as I have also told you in time past, that they which do such things shall not inherit the kingdom of God. Would Christianity have me believe in [the existence of] witchcraft, too!?