Samsung has developed a sentry robot with machine guns on it that will kill on sight.
The $200,000 killing robot has a camera for the daytime and an infrared camera for the nighttime and can tell the difference between people and trees.

No word on if it can differentiate between terrorists and trick or treating children dressed as terrorists . It has a speaker to warn people that they're about to get their face blown off by a gun-wielding robot.
This perfect killer will be set up on the DMZ separating North Korea and South Korea next year, as if you needed another reason to stay the hell away from the DMZ. If you're rich enough you can use em for your own home security