The current arc on All My Children (what? I was watching One Tree Hll reruns on SoapNet!) has Susan Lucci playing Erica Kane and her devious double, with the evil twin recently sleeping with Erica’s man. This is by no means the first time that fiendish doppelgangers have seduced their lookalikes’ men, because screwing the boyfriend/lover/husband is the best way to screw over your goody-two-shoes double.
Faith/Buffy – Buffy the Vampire Slayer, “Who Are You”
This is one of my favorite episodes of the entire series, where Faith (Eliza Dushku) switches bodies with Buffy (Sarah Michelle Gellar) and sends her opponent to jail (in Faith’s body) while she goes out to enjoy Sunnydale. Surprisingly, no one is able to discern that this isn’t the real Buffy, despite her dark lipstick, penchant for leather, and open mockery of Willow and Tara’s relationship. (This could be because Faith’s behavior is close to the moments of darkness Buffy’s experienced over the years.)
Faith is fascinated with playing the good girl, especially where it comes to Buffy’s relationships: In a great scene she details for Spike how hot the sex between the two of them would be, only to retract her offer by saying, “It would be wrong.” That doesn’t stop her, however, from going after Buffy’s boyfriend Riley. This scene gets me every time; she wants him to basically tear Buffy apart, and he wants to make love to her — something that Faith could never be comfortable with. (If you have a Hulu Plus membership, you can watch the episode here.)