Mister Mind is a strange insect-like creature that's an enemy to the DC version of Captain Marvel, Booster Gold and a few other DC superheroes.
Although each member of the Marvel family has there own individual archenemy. Mister Mind holds the title of being the archenemy to the family as a whole. And has proven on multiple occasions, that despite his dimunitive size, he is truly there most evil and dangerous opponent.
Mister Mind claims to be the world’s wickedest worm. He claims that he and his species came from Venus and that his species ruled all of the Earth in between the extinction of the dinosaurs and the very first first Ice Age. He wants to take control all over the world. But so far his plans have been failures. Many of his plans are motivated also by getting revenge on the marvel family for foiling his initial plan, and in the process he's killed untold hundereds.
Batman the Brave and the Bold
In the episode "The Malicious Mister Mind" Mind convinces the Monster Society of Evil to make him their leader which they do after a vote. He later had the society steal parts for a death ray he is constucting. He manages to defeat the Marvel's by making them turn on each other through mind control. When he finishes the death ray Doctor Sivana turns on him and uses the ray on Mind.However he reveals that it is really a growth ray which turns him into a giant monster. The Marvel Family joins forces to fight him but he defeats them. Batman then leads him back to the rays, turns it to reverse, and reverts him back to origanal size.