M.U.G.E.N

M.U.G.E.N (also known simply as MUGEN) is a freeware 2D fighting game engine designed by Elecbyte, written in C which originally used the Allegro library. The latest versions of the engine now uses the SDL library.

Spot
Spot (referred to as Cool Spot) is one of thousands of downloadable characters, available here. It was created by fer619.