She's a Man, Baby, a Man!

When Phoebe starts having dreams about seducing and killing men, Piper and Prue discover that Phoebe is somehow connected to a femme fatale demon called a Succubus. Upon learning that the Succubus is killing and draining her victims in order to reproduce, Prue takes it upon herself to cast a spell where she becomes a man in order to stop the Succubus. While Prue is under the influence of her spell, she encourages Piper to go out with Dan.