Thumbskull first appeared in "Last Laugh" as a henchmen working under Zombozo. He later then appeared in "Ghostfreaked Out" when the Circus Freak Trio went solo and they were forced to work under Ghostfreak until his defeat. Their last on screen appearance was in "Ben 10 vs. The Negative 10" in a league of Ben’s villains known as the Negative 10 working under the Forever King to steal the Sub Energy for him.
He was easily beaten by Ben, normally even worse than the others were. His name is a play on the insult "numbskull”, as well as the obvious appearance gag.
Ben 10 Omniverse
Thumbskull appears in "Something Zombozo This Way Comes" when he and his team are rehired by Zombozo to distract Ben while he is feeding off people's fear.
Powers and Abilities
Thumbskull has incredible strength (though inferior to that of Four Arms). However, he also has limited intelligence, normally serving as the "brawn" of the group, as he is easily outsmarted.
- Thumbskull's name is a playful pun on both words "thumb" and "numbskull".