The Hamburglar was McDonald's striped-shirt thief in early McDonaldland advertising.
The character was introduced as a mischievous figure who tried to steal hamburgers. His black-and-white striped clothing, mask, and later cape made him visually distinct from other McDonaldland characters. The Hamburglar's role gave McDonald's advertising a simple recurring story: a character wanted the food, while Ronald McDonald and his friends protected or enjoyed it.
The character's design changed over the years. The earliest version looked more like a small, villainous adult, while later advertising presented the Hamburglar as a shorter, younger character. Those redesigns can make archival images look unrelated even though they represent the same branded character.