A (sort of but not really) comical thing I saw many years ago at a gig... the warm-up band had played, I'll never forget, they were called Blade Runner... drummer was a funny character, about a 45 yr old rocker with frizzed har and spandex, playing with a bunch of guys that were like 18 or so who are very inexperienced. I think this was their first gig. He always had a very sly "I am up to something" look on his face. Always has some angle. His name was, aptly, "Smiley."
A brief humorous aside before continuing, these young kids had obviously had rock-n-roll fantasies in leading up to this... guy in the band walks to the edge of the stage during their rendition of "Smokin' in the Boyz Room" with a pack of cigarettes. Obviously they had imagined a throng of fans pushing up to the stage... so he tosses the cigarette pack theatrically into the throng... which isn't there. Hardly anyone there at the time (outdoor party gig, bonfire/night etc). The cigarettes land anticlimacticly on the grass to silence.
So anyway, their set ends with Smiley playing a 10 minute drum solo while the rest of the band has gone somewhere to get high or something. This is on a semi flatbed. He ends by doing a jump from the riser like David Lee Roth, theatrically with legs kicked way out.... when he lands the semi flat bed flexes and "bounces". ALL their guitars go flying off their stands! The sound of a smattering of applause slightly muffles the sound of clattering guitars. He looks around, sees no band members, and puts them quietly back on their stands, and sneaks away like nothing happened.
Of course the band returns for their next set, none the wiser... they didn't tune again before the 2nd set (inexperienced). 1st song starts with a drum intro, and when the band comes in, it's the most god-awful, out-of-tune racket you've ever heard. They are puzzled and struggle through to the end... then one guy notices a chip on his guitar... then another guy... bad moment for them. I don't know if they ever found out what happened.