The Cosby Show
Wikisimpsons - The Simpsons Wiki
In the Cosby episode where Murphy appeared as a guest, Bill Cosby introduced him to the kids as "Grampa Murphy". The kids said that they already had three grampas, and Cosby countered with "This one's a great jazz musician." The kids then replied (in a bored and indifferent manner), "Oh, they all are." In response, Cosby went into a monologue where he said that kids weren't into jazz music anymore, because they listened to "the rap music which gives them the brain damage". He then compared jazz music to commercial products such as Jell-O Pudding Pops, Kodak film and New Coke.
Bleeding Gums didn't have any lines in his guest appearance; all he got to do was stand there holding his saxophone while Cosby talked.
 Behind the Laughter
 Simpsons Farewell
Around May 1992, which is when The Cosby Show last aired, The Simpsons' producers added a tiny clip at the end of a rerun of "Three Men and a Comic Book" a few seconds after the credits. In it, Homer and Bart are watching TV when an image of Cosby (captioned with the show's title and original-run airdates) appears. Homer and Bart then have the following conversation: