Role in the episode
When Randy Cunningham refuses to finish off Hannibal McFist in Scrap City's arena, the red Punk-Bot activates the Destructo-Bot, which emerges from its hiding spot beneath the cables leading up to the announcer's chair. With exhaust bursting from its vents, the killer robot starts coming after Randy and McFist, intent on finishing them both. Randy leaps over the machine as its flamethrower nearly torches him.
As the Destructo-Bot corners McFist near the gate leading into and out of the arena, Randy uses his chain sickle to pull one of the robot's buzzsaws into its own mouth, shredding up the circuitry in its back. With several of its wires severed, the robot spins wildly around, slicing up the gate in the process (and narrowly missing McFist). Finally, the Destructo-Bot's remaining buzzsaw comes right down on its own head, splitting it right down the middle and destroying it.