Atomic Flounder
The Atomic Flounder is a retired villain who can blast people, with his atomic breath. He fought Mermaid Man and Barnacle Boy. In The The Bad Guy Club for Villains, he resembles Harold.
Looks
In The Bad Guy Club for Villains, he has a shark fin, 2 fish hands and legs, a human hand, 2 alien eyes, and has a shark tail.