Chompasaurus

Chompasaurus is an aquatic dinosaur resembling a plesiosaur who lives in the lake inside the mountain of Terrydactyland. Despite being given a title, he isn't a boss. When you first encounter him, he swallows Banjo and Kazooie whole. However, once they're inside, Chompasaurus explains that he has a stomach problem and that he needs their help, in exchange for not digesting them, which leads to an FPS minigame. Once the job is done, Chompasaurus spits the duo out and rewards them with a Jiggy. (Which he originally thought was a biscuit.)

Trivia

 * During the character parade, Chompasurus is seen with a caveman that is labelled "Lunch," which he will eat.
 * One thing that is strange that ought to be noted is where exactly Chompasaurus comes from. If one goes swimming underwater in the same area he is nowhere to be found. Also there aren't many rivers that lead into the cave he is in (only one).