The episode: “Parts: The Clonus Horror,” ep. 811
The riff: Sung in a garbled voice by Tom as the movie’s pensive hero walks in the woods. It’s rather difficult to hear exactly, but I was able to piece it together.
The explanation: This is an excerpt from the song “Corner of the Sky,” which was part of the 1972 Broadway hit “Pippin,” a loosely based (read: made up) account of the relationship between Holy Roman Emperor Charlemagne and his son, Pippin. Tom sings the song because its lyrics about not fitting in and wanting to escape mirror the emotions of the movie’s clone hero. The writers seemed to think this riff was pretty obscure, so you can actually hear Mike mumble “Pippin?” after Servo’s line. An item of unrelated interest: the 2005 Michael Bay movie “The Island” is pretty much a direct rip-off of “Clonus.”
Novelty factor: I’ve never heard the song before, although I have heard of “Pippin” off-hand. As it turns out, the musical is actually having another Broadway revival in 2013, so this joke has just become relevant again.