First it lost its tether, which supplied it with power, and now its battery-powered bulk has been brought down to size. The latest generation of Boston Dynamics' bipedal bot, shown off on Tuesday, is quiet, slimmer, more compact and more capable of dealing with bullies.

Initially developed for the DARPA Robotics Challenge, Boston Dynamics' Atlas humanoid robot has come a long way over the years. The last version of the robot was 6 feet tall and weighed in at 330 pounds, and the build before that one had to be tethered to a power source. The latest build of the Atlas robot is 5 feet and 9 inches and weighs 180 pounds. Like its predecessor, it also runs on battery power and can walk among humans without being leashed to a power source.

This latest version of Atlas was designed for operation both indoors and outdoors, says Boston Dynamics.

"It is specialized for mobile manipulation, says the company. "It is electrically powered and hydraulically actuated. It uses sensors in its body and legs to balance and LIDAR and stereo sensors in its head to avoid obstacles, assess the terrain, help with navigation and manipulate objects."

In Boston Dynamics' video of the new Atlas, the robot can be seen opening a door and walking over uneven terrain. Atlas appears to balance itself quite well, at least less clumsily than when it was first sent into the wild in August last year. But about a minute and a half into the video, things really get rough for the bot.

The robot is antagonized into showing off some of its key abilities. If something is knocked out of its hands, it'll track back to the dropped object and attempt to pick it up – that's true even if the item is being actively moved away from Atlas.

For the empaths out there, the latter part of the video may be just a tad unsettling – that's when Atlas is pushed down from behind. And for those worried about a future filled with superintelligent robot overlords, watching Atlas respond to the push may be more unsettling for another reason.

Check out the new Atlas and find out what Boston Dynamics has been up to.