S1·E20 Control Freaks

Sam rebels when her overprotective parents forbid her from attending the strange Goth circus that's come to town. Little does she know that the circus performers are ghosts, under the mystical control of the creepy ringmaster named Freakshow, who also uses the ghosts to loot the town. When Danny falls under Freakshow's spell and joins the circus - and the robbery spree - Sam must operate under the radar to destroy Freakshow's magic crystal ball, free Danny and get grounded, big-time.