Robots aren’t often athletic. But in this new video, a prototype version of a robot sponsored by the Pentagon’s blue-sky researchers climbs over wooden blocks, jumps while maintaining its balance, and climbs up stairs — the kinds of athletic tasks that Darpa wants robots to perform in order to aid with disaster relief.

This is the Pet-Proto, a cousin of the PETMAN humanoid robot manufactured by Boston Dynamics, makers of the headless BigDog robo-mule. Darpa released video of its athletic prowess on Wednesday as part of the next phase of its latest grand challenge, an effort to vastly expand the capabilities of robots so they can help repair meltdowns at nuclear plants, rescue people trapped in collapsed buildings, and assist with other disaster-mitigation efforts.

The skills that the Pet-Proto performs in the video are somewhat indicative of what Darpa wants out of its Robotics Challenge, announced in the spring. Contestants will have to go beyond the state of the art: Darpa will make the competing robot designs drive cars; walk over an uneven, debris-strewn surface; climb shaky industrial ladders and catwalks; use power tools to break through a concrete panel; find and close a valve near a leaky pipe; and replace a piece of industrial machinery like a cooling pump. There’s a reason Darpa calls these things challenges. At the end of a 27-month gauntlet of tests, the winning team will get a $2 million prize.

Only Pet-Proto won’t be competing. Boston Dynamics is working on a yet-unfinished descendent of Pet-Proto, called Atlas, that teams will use as a testbed to design the advanced software for a disaster relief ‘bot. (Darpa released this video to show what tasks it expects Atlas to perform — and, perhaps, surpass.) Those teams, unveiled Wednesday, hail from RE2, the University of Kansas, Carnegie Mellon, the Massachusetts Institute of Technology, TRAC Labs, the University of Washington, the Florida Institute for Human and Machine Cognition, Ben-Gurion University, NASA’s Jet Propulsion Laboratory and TORC Robotics.

They’re not the only teams competing in the challenge. A different group of teams won’t use Pet-Proto or Atlas at all: They’ll create their own robots and the software for them. Some are new designs modeled off existing work, like the Guardian robot that Raytheon adapted from its exoskeleton projects. Others are modifications of existing designs, like the “dextrous humanoid” Robonaut that NASA’s Johnson Space Center entered — a version of which is at work on the International Space Station.

Getting a robot to climb across an industrial catwalk and operate power tools is a massively complex endeavor for robotic mobility and autonomy. Dennis Hong, the Virginia Tech engineer who entered the challenge with a modification of his titanium-springed Autonomous Shipboard Humanoid, sums it up like this: Some engineering problems are hard, and others are “Darpa-hard,” meaning they’re theoretically resolvable but practically maddening. “We consider this beyond Darpa-hard,” Hong says. His robot better be one serious athlete if he wants to win.