1,134. A Magic Show

166:4 The Sages defined soothsaying as one who holds the eyes, meaning that he deceives people so that it appears to them as if he has done some amazing or supernatural thing. Really, all he has done is to perform some sleight of hand in order to deceive them. Those who do such things even for entertainment violate a negative commandment and the one who hired him violates "lifnei iver" (not putting a stumbling block before one who is "blind" in a certain matter). One who has the ability to object must do so and it is certainly prohibited to watch such a performance; if a non-Jew is performing, it is permitted to watch. (Nowadays, everybody knows that "magic shows" are just sleight of hand and in no way supernatural, so they are permitted - Iggros Moshe YD 4:13.)

166:5 It is forbidden to request anything from a sorceror except if one's life is in danger. If one thinks he is ill because of sorcery, he may seek treatment from a non-Jewish sorceror.