Karla Foreman

Karla Foreman was the main villainess from "Sam, Interrupted," a Season Five episode of Supernatural.

She was played by Lara Gilchrist.

Karla Foreman was a nurse at a mental hospital where Sam and Dean intentionally get themselves committed to in order to investigate a series of murders at the facility. After learning that the victims' brains were sucked out, Sam, Dean, and fellow hunter Martin Creaser figure out that the murders were committed by a wraith, a creature that feasts on brains. Karla turned heel when she was revealed as the wraith in front of Dean and Martin, who witness her feeding on a female patient. Karla feeds on her victims through a retractive spike that slides through her right hand. After fighting Dean and Martin, the evil Karla set her sights on Sam, while relishing feasting on his brain because of the mental damage inside. Dean catches Karla in the nick of time and fights with her, but she unleashes her spike to use on Dean. At that moment, however, Dean breaks the spike, causing Karla to scream in pain. She charges at Dean, only for Dean to kill her with a silver scalpel.

Trivia

 * Lara Gilchrist previously appeared on Supernatural in Season One's "Scarecrow," but not as a villain.