The Hamburglar was the hamburger thief character introduced in McDonald's advertising in the 1970s.
The character became part of McDonald's fictional advertising world, where he repeatedly tried to steal hamburgers. His striped clothing, mask, and playful behavior made him recognizable to children and helped distinguish him from the restaurant's other mascots.
The Hamburglar appeared alongside characters including Ronald McDonald, Mayor McCheese, and Grimace. McDonald's later redesigned him, giving the character a more modern appearance while retaining the basic name and hamburger-centered identity.
The name is a pun on “burglar” and “hamburger.” That wordplay is why the character is sometimes misremembered as a generic thief, but the canonical McDonald's character name is The Hamburglar.