Robomechabotatron was an ancient and supposedly powerful multi-personnel battle-mech which was built for the original purpose of opposing the forces of evil across the known galaxy. The mech's first appearance was in Season 2, when the show's protagonists presumed that such a potent weapon was the only thing that could defeat Dominator. Unfortunately, due to the incompetence of its pilots, and Wander's protest to the idea of participating in a giant robot fight, it was destroyed before any such fight could take place.
Robot Fight- Wander Over Yonder scene