It was a much-overused prank in my PT6 days. Somebody would hide under the starboard engine where the pilot couldn't see him (co-pilot usually still closing the door or heaving bags around) and hang on to the prop-tip while the guy was starting, the idea being to flummox him when he heard the bangers going and the turbine spooling, but saw no prop-movement. Obviously it would be a short time only until the prop would overpower the hand and would go from 0 to serious revolutions in seconds, whilst the hand would go scurrying backwards to safety, banging his head on the flaps on the way for his trouble.
