It turns out that giant nuclear-radiation-proof battlebots exist, and are nothing new. Meet "the Beetle," built in 1960 for the Air Force Special Weapons Center—by General Electric's Nuclear Materials and Propulsion Operation division—to service and maintain a planned fleet of atomic-powered bombers.
11 feet in height, the Beetle weighted in at 77 tons. The name was a reference to its beetle-like arms.
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To drive the Beetle, you needed to open the 15,000-pound canopy using hydraulic lifts and climb into the cockpit. Once inside, it was cramped, but you had a/c, a TV, and, of course, an ashtray. The Beetle never saw active use, and its current whereabouts are either unknown or secret.