When Frasier asks Niles to stand in for him at his radio show, Niles tells Frasier that he couldn't presume to fill his "big floppy red shoes" likening Frasier to a clown. Kelsey Grammer, who plays Frasier, has a recurring role on The Simpsons as Sideshow Bob, once-sidekick to Krusty the Clown, now a homicidal madman who wears big red shoes over his giant feet.