When DMing Queen of the Demonweb Pits in the 1e days, the player of the magic-user was facing Lolth alone by the end. He made a valiant effort, but was down to his last hit points, and decided he had nothing to lose by breaking his staff of the magi. BOOM! Killed Lolth (who fortunately only had 66 hp in 1e), and was lucky on the followup percentile roll, finding himself teleported to another plane (I don't recall which, but it was somewhere nice) instead of blown to smithereens. Definitely one of the high points of my entire gaming career.