Serial Killer Shapeshifter

Serial Killer Shapeshifter was a main antagonist in the Supernatural episode Skin first season.

History
Not much about Shapeshifter's life beyond his monster status making him more hateful than his own specimen, he began to become a serial killer. Then the Shapeshifter without his murders and he would become one of his dear ones and kill one while he incriminated them. He disguised himself as Zach Warren and killed his girfriend. Sam learned of the incident with Zach's sister, Rebecca, he insisted for proof that Zach was innocent.

After seeing a dog bark, the Winchesters realize that they are dealing with something supernatural and decide to investigate. Later at the same time, the Shapeshifter turns into Alex and tries to attack his wife Lindsay, but he is caught in the act by Alex, who preferred to leave early. The Shapeshifter knocks out Alex and escapes manking it look Alex had killed Lindsay. Sam and Dean realize they are dealing with Shapeshifter although they have never fought one before. They investigate the sewer and find the Shapeshifter escapes again. And when the Winchesters chase the Shapeshifter, he ambushes Dean and locks in his lair. And then he turns into Dean, to ambush Sam, that Sam can see him through his disguise, and when Sam hesitates to kill him, he runs off and goes after Rebecca.

Then the Shapeshifter uses Dean's appearance and tries to convince her by talking about the murders to approach her to kill her. Howerver, he begins to scare her that when tries to call the police, he then attacks and ties her, and when before he can kill her, the police arrives causing him to escape and injuring a policeman on the way and incriminating Dean.