Party Bears

The Bears make their first appearance in "My Two Favorite People," where three of them get free Power Rings from the Forest Wizard. Along with the Forest Wizard, they are scared off when Jake used his Stretchy Powers to enlarge himself, and charged into the meadow they were frolicking in. Some of them appear in "When Wedding Bells Thaw," dancing during Ice King's manlorette party montage.

In "Belly of the Beast," they make a new "party cave" inside the stomach of a Giant under the leadership of their chief Party Pat, not realizing where they were or the danger they were in. The bears are known to make their own beverage, Honey Energy Drink. Though they weren't in immediate danger of being digested by the Giant, they were hurting it with the fireworks they fired off in its stomach. The pained Giant tried more and more extreme means of stopping the pain, going so far as to drink molten lava to drive the bears out. Finn and Jake were forced to go in and try to stop the partying. Finally, after being lead out of the Giant's digestive tract, the bears and the Giant made amends under the condition of using red laser pointers for partying instead of fireworks.

Appearance
The Bears are small bears, usually in varying shades of brown with symbols on their bellies. Each bear has a different random symbol (e.g. a hamburger, a tree, a PHIL FACE, etc.).

Trivia

 * The marks on their bellies are references to the "cutie marks" and "tummy symbols" in the My Little Pony and Care Bears franchises, respectively.
 * The marks are not symbols like fruit or happiness; they are more random, such as the "poo" and the "shooting star" ones.
 * They are "party animals." This trait was firmly established as their way of life in "Belly of the Beast."
 * There is a bear with a cartoonish symbol of feces on its stomach, perhaps making it a "Poo bear," a subtle reference to Winnie the Pooh.