The toughest villains are the ones who absorb the hero's powers and throw it back at them. In the car world, the Volvo XC90 is playing the role of that villain; it siphoned the energy of other cars on the road to get a charge.
The trick from the Swedish car manufacturer took place on a California highway, where the company laid down a patch of road that would suck up unused energy from cars that passed over it. That power was fed into an awaiting XC90, which was able to drive off the work of other cars.
The energy capturing system Volvo built used hydraulic power to transfer power from the road to the XC90. A mat containing tubes filled with water was placed on the road; when a car drove over the mat, it compressed the tubes and drove the water into a roadside tank that converted the hydraulic energy into electric energy.Every time a car passed over the mat, it filled the tank of the XC90. To truly troll the passersby who powered up Volvo's hybrid vehicle, the company installed a sign that thanked the cars for the help.
Of course, scoring energy this way is pretty impractical for any real or longterm applications; as far as we know, Volvo isn't selling the energy-stealing mat with the car to set up in your neighborhood.
That doesn't stop it from being a fun little prank to play on the other cars on the road. Perhaps Volvo should consider swapping out its current logo for a trollface.