About a year ago, there was a 777 that was starting an engine during pushback (using the APU). Unfortunately the crew had neglected to place the throttle to idle before initiating the start - as soon as the engine started it rapidly accelerated to power.
The aircraft rotated into the tug and the (running) engine impacted the tug. From the event report "
The pushback tractor driver, during these events, run away from his position in the tractor’s cabin…" 
Miraculously no serious injuries, but considerable damage to both the airplane and the tug. Presumably there was also damage to the tug drivers underwear
