Take a look at the video link below and watch it in full-screen. Some fellow has created a remotely controlled quadro-copter fitted out with a 100 round machine gun. Watch him as he has fun blowing up mannequins and cars.
It is all done with a touch of humor but the reality is that this fellow has created a very lethal killing machine that could be remotely controlled and come into your yard, or house and kill everyone there. Then fly away or self-destructed.