Captain Marvel comic book villain/spy (real name Kurt Filpots) who sent the Axis powers secrets coded in the notes of his banjo playing during World War II. He first appeared in the "Captain Marvel and the Amazing Case of the Code in Music!" story in Fawcett's Captain Marvel Adventures
issue 8 (March 6, 1942). He looks comical, but he's a cold-blooded killer. He turns out to be criminal mastermind Dr. Filpots, head of an international spy ring, and in league with the Japanese.
He also appeared in one panel as part of Mr. Mind's Monster Society of Evil in Captain Marvel Adventures #22 (Mar 26, 1943).