The Hamburglar was created as a hamburger thief in McDonald's 1970s McDonaldland advertising.
The character was part of a fantasy setting populated by McDonald's mascots and fictional personalities. His recurring story involved attempting to steal hamburgers, especially the chain's signature burgers, while other characters tried to stop or expose him. The concept gave McDonald's advertising a continuing narrative rather than relying only on product descriptions.
The Hamburglar's appearance changed substantially. Early versions looked more like a short, wild-haired adult criminal, while the later version was a smaller childlike figure wearing a black-and-white striped outfit and cape. Those redesigns are why depictions from different periods can appear unrelated.
The Hamburglar is distinct from Mayor McCheese, who was a civic leader in McDonaldland, and from Captain Crook, another villain associated with Filet-O-Fish advertising. All belonged to the same broader character-based branding era.