It's time to take out the trash!
Oscar is a muppetus grouchus, or a green muppet that lives in a trash can in Sesame Street and always screams at people for dumb reasons. He was born in his trash can twenty years ago, and has never actually left it, except for when he went to Grouchland. We believe he actually doesn't know how to walk. He is currently facing eviction from his garbage can because Mitt Romney is trying to close down Sesame Street.
After the Elmo Gang came to power, Oscar was on board right away, having a love for destruction, misery, and free ice cream. He eventually became one of Elmo's least favorite mob members, but Elmo let him live, because Oscar was simply so good at being bad.
Oscar died three years ago under mysterious circumstances. Then, everyone realized he was still alive, and he was actually just taking a vacation in Pac-Land when he was gone. Oscar is now wanted in every place in the world except for Sesame Street. Oscar always carries an AK-47, however, and Nobody argues with him, because they know what's best for them.