Supernatural (2005)

S1E6 Skin

Sam and Dean are called upon to help Sam's former college friend, who finds himself wrongfully accused of murder. Determined to prove his innocence, the brothers uncover a shapeshifter that has been mimicking various individuals to carry out its deadly deeds. The situation escalates dramatically when the shapeshifter takes on Dean's appearance, forcing the brothers into a tense and dangerous confrontation as they race against time to stop the killer before it's too late.