Here's one that happened to me almost 30 years ago back when power tools (saws, angle grinders, etc.) didn't have those safety trigger mechanisms that they have now. In this case it was a 9" angle grinder which back then they all had a switch/trigger which could be locked on. Anyway I grabbed the 9" angle grinder from our tool store, sat it on the ground (disc facing downwards), reached up and plugged it in to the suspended power lead (permanent type, suspended with a light chain) and hey presto... it had been left on (locked on) and therefore went into action (full speed) whilst moving about due to the vibration of the motor, right next to my two feet. I went into "disco dancing" mode trying to avoid the thing and was able to rip the cable out of the lead soon after.
I'll never forget that one!