 Unable to work with the rest of the cast, Jones recorded his lines at the Village Recorder in West Los Angeles; he chewed on a cookie close to his microphone to perform drooling sounds for the aliens.The sibling aliens Kang and Kodos first appeared on the show on this episode.Every "Treehouse of Horror" episode since this one must have Kang and Kodos as characters, states an unofficial "Simpsons" rule.