Imagine how difficult it is to climb a rock wall. Now think of how much more challenging that would be with just one arm. That's what happens in a DARPA video that shows how one U.S. Army amputee was able to make an ascent with help from an electric prosthetic called the DEKA Arm.

The arm has earned the nickname “Luke,” after Luke Skywalker (spoiler alert) had his arm severed in a light saber duel with his father, Darth Vader, in “The Empire Strikes Back.”

The Defense Advanced Research Projects Agency first developed the DEKA Arm to benefit wounded combat veterans. Unlike other prosthetics, it is controlled by sending electric signals from actual muscle, controlling the prosthetic joint movements as if the user was born wearing it. The FDA approved the DEKA Arm for sale to the general public last year, but it was a military service member whose demonstration of the device at Walter Reed National Military Medical Center has gone viral.

Even if navigating a rock wall isn't something people do every day, previous DEKA Arm demonstrations have made it clear that the prosthetic can also be used for more mundane tasks. Here, in a video posted on DARPA's website last year, one user shows that the device provides enough subtle control to pick up eggs.

The DEKA project began in 2006, after being developed by Dean Kamen, the inventor of the Segway.