I once had a robotics professor who argued cruise missiles meet most definitions of 'robot'. Meaning, of course, that we've had killer robots for decades.

(I suspect his larger point was that, if you try to come up with a definition which includes an industrial robot arm, a bomb disposal robot, and a robot vacuum cleaner, those things don't actually have much in common - so your definition will sweep up a bunch of things that most people wouldn't call robots)