Bart Simpson; Klaatu; Mayor Quimby; Kent Brockman; Grampa Simpson [Abe Simpson]; Hans Moleman; Jasper; Nelson Muntz; Ralph Wiggum; Sherri; Terri; Comic Book Guy; Milhouse Van Houten; Chief Wiggum; Lisa Simpson
Synopsis
Bart teaches an alien visitor, Klaatu, how to play practical jokes on people.