9. Mr. Banjo
Like Turner D. Century, Mr. Banjo is a criminal who wears an old-fashioned green suit and straw hat. (Also no, I don't know if that garb is a prerequisite to being a terrible supervillain.)
This apple-cheeked assassin battled Shazam on two occasions during World War II. As an agent to the Axis powers, the malevolent musician used his banjo to play secret messages on the radio, which the Japanese decoded to learn of the US army's strategies. In their first encounter, Shazam defeated the musical menace by whacking him with his own banjo.
Two issues later, Mr. Banjo returned with a new plan to win the war: hire a fake defence chief in Washington DC to give out fake orders. What does this scheme have to do with banjos? Absolutely nothing. In his second (and final) appearance, Banjo doesn't use a musical instrument at any point, which begs the question why the writers implemented him into the story in the first place.
The lyrical lunatic was defeated after Shazam placed him on a hook, where he was attacked by bats. A ridiculous conclusion to a ridiculous supervillain.