|Vehicles and/or Gadgets||None|
|Occupation||The Bear's Party Cave|
The Monster is a major character in the episode "Belly of the Beast" as most of the episode takes place inside his stomach. He first appears after waking Finn and Jake by screaming and shooting fireworks from his mouth. The duo initially believe that he is part of a dream; only after it kicks Jake and they hear a cry for help from its belly do the two realize that the monster is real.
After entering his mouth, Finn and Jake are surprised to find a colony of bears partying inside the monster's belly, and after unsuccessfully trying to save the bears from being digested, Finn unwittingly makes a comment about how the only way the monster could kill the bears for sure would be for him to swallow "some deadly volcano lava." Overhearing this, the monster makes way for the nearest volcano, while Finn and Jake race to get the bears out as fast as possible managing to get every last bear out safely.
After the bears were fully patched up (the monster also receiving treatment on his butt and tongue), Party Pat tells Finn that his colony needs a "phat party club to grind in" and that the monster's belly was the best place to do so. Party Pat resolves to replace the fireworks they were previously using with "gentle lasers." The monster accepts this agreement and takes the bears upon his gut once more.
In "Billy's Bucket List," the Monster provides the backdrop for Finn and Rap Bear's rap battle.
- In the TV series, the Monster is voiced by Dee Bradley Baker.
- He's only appeared in A Book and a Bad Guy as an entrance to the secret area.