Robotic Technology Inc.'s Energetically Autonomous Tactical Robot — that's right, "EATR" — "can find, ingest, and extract energy from biomass in the environment (and other organically-based energy sources), as well as use conventional and alternative fuels (such as gasoline, heavy fuel, kerosene, diesel, propane, coal, cooking oil, and solar) when suitable," reads the company's Web site.
Please note that the biomass the robot consumes to power itself will be "whatever organic material it can find — grass, wood, old furniture, even dead bodies." Much to my chagrine, the article does not say how the robot will differeniate between dead bodies and live ones. But it does mention that "Robotic Technology presents EATR as an essentially benign artificial creature that fills its belly through 'foraging,' despite the obvious military purpose." Essentially benign, except when you piss it off.
Hat tip to DrewM. at Ace of Spades, who suggests that "when Skynet becomes self-aware and we try and shut it off it will simply kill us faster so it can eat. Great." Not to worry though, Neo will eventually free humanity at the close of the 22nd century.