"The Cat Came Back" was sung by Rowlf in The Muppet Show episode 523. Gaffer, in a rare onstage appearance, played the titular cat opposite owner Benny. Among the many dogs who appeared in this number were Rover Joe, Wolfhound, and Baskerville.
The song is a popular children's and folk tune which has evolved from a minstrel number of the same name written by Harry S. Miller in 1893. Multiple versions with a wide variety of verses can be found.