As sung by Phoebe (Lisa Kudrow) on Friends (though the mere lyrics simply don't do this song justice):
Smelly cat, smelly cat
What are they feeding you?
Smelly cat, smelly cat
It's not your fault
They won't take you to the vet
You're obviously not their favourite pet
You may not be a bed of roses
And you're no friend to those with noses
Smelly cat, smelly cat
What are they feeding you?
Smelly cat, smelly cat
It's not your fault...
A running joke on the show was to pair Kudrow with a guest star who was of the musical bent. During the end credits, the two would sing this song, usually with Kudrow's character denigrating the musician's interpretation of the song. The two musicians I can recall are Chrissie Hynde and Chris Isaak, though I'm sure there were more...