What is the song called on the tuba that fallows a fat man?

The song you’re referring to is likely "The Elephant" from "Carnival of the Animals" by Camille Saint-Saëns. It is often associated with the tuba and commonly depicted in performances featuring a large character or figure. The piece is playful and evokes the imagery of a large, lumbering creature, making it a popular choice for entertaining and whimsical performances.