Grunk

Grunk was the very first supervillain during the prehistoric times.

History
He was defeated by Maxum Man when he froze him, and was set free by Eric Needles. He apparently loves Kitty rather than Vana, even kidnaps her & Eric's sandwich. He was frozen once again, this time by an angry Vana. He appears in the Season 2 episode "The Land Before Grunk".