He was voiced by Fred Tatasciore.
In the video game, King Fossa depicted as a muscular fossa larger than his minions with brown eyes and a white mane slanting down his back. He also stands on two legs, while his minions stand on all four, possibly because he's the leader. In the Netflix original, he's depicted as a normal fossa who looks exactly like his minions, except he has gray fur and has a skull with feathers for a crown.
When Alex walks into the Fossa territory, King Fossa and his minions show up and confront him. Alex tries to escape, but they reappear and surround him. However, the penguins appear and give him the claw ability from the power cards. After Alex defeats the fossas, King Fossa roars with frustration and begins chasing Alex. He begins to eat durian and breathe at Alex. Whevever he hits Alex, he would laugh maliciously at him. Whenever he gets hit by Alex with his mangoes, he would summon his vultures to protect him and fly with durians at him. Alex would have to keep throwing mangoes at him until his healthbar is completely empty. King Fossa once again chases Alex and traps him in the arena of doom. Whenever he gets angry, his fur becomes inflamed with rage and Alex would have to wait until he's tired out from attacking him so he can claw at him. He would summon his vultures, chase Alex and use durian breath against him whenever he attacks him. Once Alex has finished him off, Marty comes out of nowhere and lands on the fossa leader. Marty then suggests that they give him to the penguins to keep him out of trouble.
He also serves as a playable character in the Shuffleboard minigame, alongside Alex, Marty, Gloria, Melman, Wilbur, Big Louie and Crocky. The levels consist of a poolside, jungle bumper and Antarctic curve.
- Although his role is small, he is still the main antagonist because he is the final boss and was far more dangerous than anyone else.
- He reappears in the Netflix original show All Hail King Julien. The only difference is that he is a normal fossa and he is not as fierce as his videogame counterpart.
- King Fossa, the Zoo Hunter and Sensei Croc are the only bosses in the videogame.
- King Fossa is a slightly altered version of Diego from the Ice Age franchise.