South Park: Season 5, Episode 5

5 - 5: Terrance and Phillip: Behind the Blow

The boys are supposed to participate in an "Earth Day Brain Washing Festival," but instead go to see a live-action Terrance and Phillip show under the guise of asking them to perform at the Earth Day event. When they get there, Terrance looks terrible and Phillip is an impostor. The boys have to get Terrance and Phillip back together, but it will not be an easy task.