He was once Smudge's uncle, but went mad and decided to be as dirty as his nephew. He lives in the underworld of the sewer system and leads a large army of "dirty beings", monsters made of dirt. He also has superpowers: Apart from flying, he can release dirt beams, move objects from a distance, or create objects using dust. Water works on him just like kryptonite works on Superman: Once he's wet, all his powers are gone.
His dream is to make the entire world a dirtier place to live, and also to rule it. However, Monica and her friends always find a way to stop him. Captain somewhat has a good feeling towards Smudge, occasionally. He sometimes is the one to save him from any contact with water. On the other hand, there are strips in which he wants to destroy Smudge for Smudge being the dirtier being in the universe, a status that Captain desires.