South Park: Season 9, Episode 9

9 - 9: Marjorine

The boys have reason to think that girls can see into the future. They decide that one of them must pretend to be a girl so they can obtain access to the girls' secret information. All they have to do is fake Butters' death, and then re-introduce him to the class as "the new girl." Unfortunately, Mr. and Mrs. Stotch believe their son is really dead.