The video: South Korea's robotic prison guards, charged with monitoring prison cells for suspicious activity, have arrived — and they look a lot less friendly than the last time we saw them. The autonomous, mood-sensing droids are touted by Reuters as the "world's first robotic prison guard," and will be used to relieve overworked guards of mundane patrolling duties. The 5-foot-tall "Robo-guard" comes equipped with advanced 3-D cameras and microphones to detect signs of erratic or dangerous behavior — to prevent things such as suicide attempts — and can summon human allies when necessary. The bots are controlled from either a computer terminal or an iPad, and can serve as a two-way communications console between prison staff and inmates. Best of all: When the machine's power dips down to 20 percent, it automatically returns to its charging station. Three "Robo-guards" will be field-tested in the South Korean city of Pohang at a cost of $900,000, which officials hope will eventually cut down on labor expenses. 

The reaction: "Robo-guard" looks "pretty different from the last time we saw it," says Dan Nosowitz at Popular Science. The machines are "a little less cheerful, a little more Cylon-y" — like the robotic villains of Battlestar Galactica fame. But on the bright side, it's a good thing we don't have to worry about these machines taking over Terminator-style, says Sam Byford at The Verge. The most Robo-guard can do "is summon correctional officers to the scene to handle the problems themselves." Have a look: