Killer robots may have already proven their lethality on the front lines of the Ukraine war. But China is experimenting with “wolf packs” of AI-controlled hunters to prowl the alleys, basements and attics of our cities.

Robots competed in a half marathon race in Beijing on Sunday, with the winning machine leaving its human rivals for dust.

Walker S2 is an adult-sized humanoid robot with legs, a torso, and arms. China is sending these robots to patrol their border with Vietnam.