Did you notice.....
the tapioca pudding at the SNPP cafeteria is extremely caustic?
Mr. Burns only has one lung?
Lenny is a war hero?
Mr. Burns considers Smithers "the ol' ball and chain"?
Dr. Hibbert has a shot to GIVE somebody polio?
Mr. Burns has never heard of "Cats" or "The King and I"?
Homer knows how to do the Lindy Hop?
Smithers found a woman who looks EXACTLY like the Malibu Stacy doll for his musical?
The guy from "Mayored to the Mob" who sounds like Frank Nelson is back, and he works in the department store instead of the restaurant?
References
The Birds- the scene at the end where they were attacked by gulls.
(maybe) King of the Hill- Homer gets molested by a panda bear like Hank Hill gets molested by a dolphin.