A Huey Cobra practising autorotations during a military night training exercise had a problem and landed on the tail rotor, separating the tailboom. Fortunately, it wound up on its skids, sliding down the runway doing 360s in a brilliant shower of sparks.
As the Cobra passed the tower, the following exchange was overheard:
Tower: "Cobra 1, do you need any assistance?"
Cobra 1: "I don't know, Tower. We aren't done crashing yet."