So I made up some villains to fight Ooze, but I didn't draw them actually fighting him. So I guess these would be covers for stories? Its funny how Ooze was never meant to be a thing but he's developed into his own world.
Top to bottom, left to right.

SKULLFACE: His name mostly comes from what Ooze calls him, like Ooze he has a liquid body, but unlike him the separated parts of him can move independently so he houses parts in robot bodies. Though the original always has the skull floating in it.

Justin: A spoiled brat whose latent mutant has resulted in him developing hypnotic powers. Not so much of a villain as much as a nuisance. Still, he consistently tries to get whatever he wants using his powers, and often gets away using others as scapegoats. He goes as far as hypnotising people to carry him around and use children as human shields.

Monkey: A primordial spirit of nature, though Ooze refuses to believe this is true. He has power over nature, being able to turn people into animals, or regressing them to feral children if he prefers to use them as helpers, since animals don't tend to understand speech, or have thumbs. His powers don't work on Ooze since he is a unnatural mutation. His main weakness is simply his childish nature and his complete lack of understanding of technology.

Tar: Similar to Ooze, but the main difference being he has a thicker consistency, and this unlike him, does not require a suit to hold him together. It also means he has better control over shifting his body into different shapes, and can create chains of himself to get around. He is still limited by his original mass however, and had the same two 'cores' like Ooze, that if separated, will kill him.