Scar is the main antagonist in the popular 1994 Disney film, The Lion King. He is Simba's uncle, and makes two cameos within the series.
Mad Doctor's Lab, one of the stained glass windows features Scar. There is also a statue of him in Dark Beauty Caste courtyard.
Mizrabel briefly transforms into Scar when she first reveals herself to Mickey, along with several other villains. Despite this, however, you do not battle Scar during the game. It is presumed that he is one of the characters that weren't or didn't managed to get sucked into Wasteland from the Cartoon World.