McDonald's used to be all about their motley crew of food monsters: Ronald, the Hamburglar, Grimace -- they all lived in McDonaldland, a magical place where everything from trees to rocks was living/talking/edible, which was less horrifying than it sounds, in practice. The land was ruled with a meaty fist by Mayor McCheese, who dressed like the Joker, and had dead cow flesh for a head, yet still never managed to out-creep Ronald.
"Want to know how I got these buns?"
The Original Character:
The entire McDonaldland concept was phased out in the '70s, when Sid and Marty Krofft sued McDonald's, claiming that McCheese was actually a rip-off of H.R. Pufnstuf -- a character from a children's TV series of the same name.