Wrong. So wrong. Fossa is the actual name of an animal and I felt like a very uneducated person when I found out.
When they get bigger they even look evil, except they have noses that are quite a bit smaller than depicted in the movie:
However, when they are young they are pretty cute:
At any rate, apparently the Fossa are indigenous to Madagascar and that's probably why I've never heard of them before. And get this, the Fossa is not even a cat! It's a Mongoose, which is probably why they look like weasely little creatures. Even though they are related to the Mongoose they can grow to be six feet long, which is probably why they were originally mistaken to be part of the feline family.
So if you ever happen to visit Madagascar, be careful because the Fossa might get you and don't try to run because it can go up to 35 miles per hour! Though you are probably a bit larger than the prey they normally go after so I wouldn't worry too much!