You know the brilliant bit in Back to the Future 3 where Marty is hanging with a noose around his neck, only to be saved by Doc? He really sold the moment, didn't he? There's a good reason for that. That scene almost killed the actor, who announced in his autobiography that the first couple of takes he stood on a box for the stunt, seeing as his whole body wasn't going to be shown, but it just didn't look realistic enough and he offered to do it without a box. Dangerously, this being the 7th take meant that Fox was getting tired and miscalculated the timing of his hand, which was meant to go between the noose and his neck, and as a result, he passed out for around 30 seconds. According to Fox, "it was a full 30 seconds before anyone noticed. Thankfully Bob Zemeckis, a fan of mine though he was, realised that I wasn't that good of an actor". The shooting was halted for the day and Fox was allowed to recover, presumably while seriously reconsidering his commitment to using stunt doubles.