On Fox last night there was a 2 hour marathon of the creator's favorite episodes. In the episode Brian Wallows and Peter's Swallows there was a subtle change in the song that Brian sings. I may give some more hints. You guess what was different.
P.S.: This is what 1 part of the alphabet would look like if Q and R are removed.
P.S.: This is what 1 part of the alphabet would look like if Q and R are removed.