One of Captain Marvel's recurring villains from the early issues of Captain Marvel Adventures in the 1940s, Kurt Filpots worked as an agent for the Axis powers during World War II. Dressed as a stout man in a shaggy green suit and straw hat who carried around an old banjo with him, Filpots delivered secrets in the form of musical notes. Although evil, Mr. Banjo would go up against Captain Marvel with nothing more than a banjo.
Mr. Banjo appeared in the Robot Chicken DC Comics Special (2012).