Friday the 13th: The Series - Season 2 Episode 20 Mesmer's Bauble

A homely record-store clerk is obsessed with pop diva Angelica, and happens to stumble upon a jewelry robbery where the thieves drop one of the items: a cursed pendant that first belonged to Dr. Mesmer. The curse lets the clerk fulfill his every wish by mesmerizing a victim into doing whatever he wants them to. He wishes first for attractiveness, and then for the diva's love and the chance to be close to her. Ultimately, however, none of this is good enough for him, and his final wish is to _be_ Angelica. The wish is successful, but Micki and Ryan, close on his trail, manage to intercept him/her at a concert and grab the necklace, undoing all the benefits it bestowed.