Which McDonaldland character was portrayed as a hamburger-stealing villain?

The Hamburglar was McDonaldland's hamburger-stealing villain.

McDonald's introduced the character as part of its fictional McDonaldland advertising world, where human-like food characters and fantasy figures interacted with Ronald McDonald. The Hamburglar's defining behavior was trying to steal hamburgers, usually while wearing a black-and-white striped outfit and a cape.

The character's appearance changed over time. Early versions were more creature-like, while later advertising presented a smaller, more child-oriented figure. Those redesigns can make historical commercials look as though they feature different characters, but they represent the same branded personality.

The Hamburglar was not a real-world mascot for a menu item in the way that some McDonaldland figures were associated with food products. His role was primarily comic conflict: he created a recurring plot that made the restaurant's advertising world recognizable to children.