Crusher is the kind of robotic juggernaut people might expect to see in action thrillers.

It rolls over cars, climbs low walls and negotiates the rockiest terrain -- and does so autonomously. What this robot can't climb over it goes around. One almost expects to see the Fantastic Four walking beside it.

The 6.5-ton armor-clad robot, which Carnegie Mellon University's National Robotics Engineering Center developed for the U.S. Army, demonstrated its titanic abilities recently at Fort Bliss, Texas, where it showed battlefield potential to keep troops out of harm's way.

By all accounts, Crusher excelled. And if some thoroughly smashed cars are any indication, it also lived up to its name.

"We really put it through the paces," said Stephen Welby, director of the Tactical Technology Office of the Defense Advanced Research Project Agency. "It was pretty exciting for soldiers and the team."

Mr. Welby said Crusher proved to be "fully capable" during its demonstration that occurred inside a 100-square-kilometer area near El Paso, which provided a "real-world test environment."

The six-wheeled behemoth resembles a tank without a turret. Not pretty, Crusher is brawny, smart and determined.

Mr. Welby said it was amazing to watch it cross difficult terrain at 6 to 7 mph, which is more than twice the speed at which humans typically walk. When it encountered a bulwark protected with barbed wire and a trench, Crusher traveled alongside until it found a weakness, then scrambled over the top all on its own.

Mr. Welby said DARPA's role is to develop technology prototypes for the military. With Crusher, that role will end after the final demonstration later this year. Then it will be the military's choice whether to continue developing Crusher for eventual battlefield use.

Steve Di Antonio, Carnegie Mellon's NREC director, said Crusher already has a strong future. For example, the software program known as UPI that makes the vehicle autonomous could be applied to various other vehicles. Crusher also has potential applications in construction, farming and mining.

DARPA determines what information can be released publicly, so Dr. Di Antonio deferred to the NREC Web site, www.rec.ri.cmu.edu/projects/upi/index.htm for more information about Crusher.

By every indication, DARPA was pleased with what it witnessed.

Last month, the unmanned vehicle traveled over sand dunes, mountainous areas, craggy rock and desert. It overcame a variety of obstacles and made its way to designated locations with only limited human assistance.

Crusher traveled 100 kilometers and counting. Because it does not have to accommodate a human crew, it's designed to be rugged and mobile.

It can carry 4 tons of payload. Not easily repelled, Crusher is protected with armor, including a hull made of high-strength aluminum tubes and titanium nodes protected by a steel skid plate that can absorb the impact of rocks and tree stumps.

Individual suspension for all six wheels enables it to move smoothly over extremely rough terrain and surmount large ditches, man-made barriers or piles of boulders. Electric motors embedded in each of Crusher's six wheels are powered with a hybrid system that uses a turbo diesel generator to recharge its batteries.

At top speed, it can rumble at 26 mph, but typically crosses rough terrain at a slower pace, albeit a pace that Mr. Welby said is impressive considering the obstacles.

"To understand how fast it operated in this environment, you have to understand that we were bouncing around [in a vehicle following Crusher], and I could barely walk afterwards with pain in my kidneys," he said.

Crusher "is a weird thing to watch."

"The software and planning improved to the point where it can figure out a way out of a problem," he said.

If adopted by the military, Crusher initially would be used to run convoys. Eventually it could be used in tactical roles and eventually to protect troops. It can be equipped with weapons and other devices that humans could operate from afar.

And based on last week's demonstration, an adverse military decision appears to be the only thing that could stop this Rambo on wheels.