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From Unmariowiki

McDonalds is a Fast Food restarunt. It is run by Ronald McDonald. It first appeared in Super Mario Bros., as an unlockable 8th level. It's boss was Bob The Builder. He attacked by throwing Crowbars at the player. Many people believed that this was racist, but it was not. Ronald Mc Donald was supposed to be the true boss, but got written out becuase he was too clown-like.