A California man has been arrested after attacking a crime prevention robot in a car park, police say.
The Knightscope machine was on patrol outside the Silicon Valley company that created it when the alleged attacker approached, witnesses say.
The 300lb (136kg) robot raised the alarm after it was allegedly knocked over by 41-year-old Jason Sylvain.
He said he was an engineer who wanted to "test" the machine, said a Knightscope representative.
Mr Sylvain has been charged with public intoxication in the 19 April incident.
The robot suffered a few scratches, but has "recuperated" and is back on patrol, said Knightscope.
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"It did what it was designed to do," said company spokesman Stacy Dean Stephens.
Alarms on the 5ft (150cm) tall robot, which is known as K5, sounded after it was knocked down, said Knightscope.
A company employee went outside to stall the man until Mountain View police could arrive.
A police spokeswoman said they were dispatched to the car park after a report of a prowler.
They said Mr Sylvain "appeared confused, had red, glassy eyes and a strong odour of alcohol emitted from him".
One local man told ABC News it was not a fair fight.
"I think this is a pretty pathetic incident because it shows how spineless the drunk guys in Silicon Valley really are because they attack a victim who doesn't even have any arms," said Eamonn Callon.