The Fossas are the main antagonists in Madagascar; they are seen in the movie as the main villains, and in Madagascar: The Video Game as supporting villains. They appear as medium-sized cat-like creatures and rarely speak, instead usually growling and yelping. Only one of the fossas said "Who? Me?"
Throughout Madagascar, they are shown to terrorize the lemurs and attempt to eat them. According to Julien, "they're always annoying us by trespassing, interrupting our parties, and ripping our limbs off." When they do speak, they put "fossa" in front of every word: ex. "Fossa hungry, fossa eat." They are terrified of Alex due to him being a lion and being much more physically powerful and intimidating. In the end, thanks to a setup performed by his friends and the penguins, Alex made sure that the fossas never bothered the lemurs ever again.
They appeared when they crashed the lemur's party. They surround Mort, they were turning him into a salad. But then Alex comes and save Mort, there was a spider on Alex's back, he screams but usu scaring the fossa. They then appear when Alex was doing a show they were watching, but when Alex roared they ran away. When Marty came where they live they start chasing him, but his friends came to fought them off, then Alex came along and scare them away from the lemur's territory.
All Hail King Julien