Mr Bumpy's Stomach
Mr Bumpy's Stomach is a character and the first organ that Mr Bumpy and Squishington encounter in the episode "Gum Crazy." He is voiced by Jim Cummings.

When Mr Bumpy and Squishington travel through a black hole inside Mr Bumpy's body, Bumpy goes off to find the Stomach so he can take the undigested Gum. 

Inside the room, they find Bumpy's Stomach, a large fat brown organ with eye stalks like Bumpy. Bumpy demands the stomach to had over the gum, the Stomach belches and sends the two flying back.

The Stomach claims that it's not his job, and he only digest the gum, he then tells Bumpy to go see the Heart, saying that he loves the stuff. Bumpy then swipes a piece of gum from the Stomach's hand, and gobbles it up. The Stomach calls for his guards to digest the intruders.