Baumann knew he'd need big tires to stomp cars, so he bought a pair of old three-ton wheels from a Caterpillar front-end loader. To power them, he used a six-cylinder diesel engine and gearbox ripped out of a tractor-trailer. Anticipating that balance would be a concern, he oversaw the construction of an inch-thick, 1.3-ton sump guard, a heavy metal plate that sits beneath the frame just five inches off the ground and keeps the vehicle's weight low to the ground. He then attached the seat and frame from an old Honda motorbike to give himself a comfy perch. And he covered the engine's innards with plates made of aKevlar-like material to protect them in collisions. "You could ram a car into the side, and you wouldn't penetrate it," he says.