Felix the Cat is the titular protagonist of the animated series of the same name (dating back to 1919) - Felix has also appeared in comics, cartoons, movies and countless other media and is arguably one of the most famous fictional, anthropomorphic cats in the world.
After saving all toons, Chip and Dale find out about a war between 3D and 2D toons, and that Gorefield is trying to kill everyone, now they must team up with Peter Pan to stop him, it's gonna be a full war.
