An Aussie doctor had difficulty starting his aircraft. It had a dead battery. So with ignition on, a little choke, and brakes OFF, he attempted to start the aircraft by swinging the prop [pretty standard procedure for prop job types . . . except the brakes].
It started OK. But since the brakes were off, the craft rolled away from him. At high taxi speed, its titanium blade spinning at 85% max RPM, it cleaned up about six light aircraft belonging to a local flying club before coming to a stop.
The attached pics show the last aircraft attacked by this runaway airplane [I haven't seen more even slices in a loaf of bread].