The episode: “Secret Agent Super Dragon,” ep. 504
The riff: Growled by Joel to finish a sentence by a wimpy-looking tough who says “Yes, you must!”
The explanation: Joel is referencing a catchphrase and exercise that appears to have first been invented by children’s book author Judy Blume in her well-known 1970 young adult novel “Are You There God? It’s me, Margaret.” The story is about a young girl entering puberty and dealing with her changing world, including envy of other girls in school who have developed faster. The exercise is the sort of fraudulent thing that kids pass around as a rumor on the playground, that by exercising the pec muscles and saying “I must increase my bust,” one could develop larger breasts. It has since become attributed to many other sources, and even songs, although Blume says it definitely doesn’t work.
Novelty factor: I had no idea. I really thought it was going to be in parody of some kind of infomercial series that would be using the phrase as a mantra.