Back to the Future Part III -- Michael J. Fox Was Nearly Hanged for Real
In the third installment of the Back to the Future trilogy, the Tannen family's genetic predisposition toward assholery is confirmed when Marty McFly travels to the year 1885 and is almost immediately murdered by the notorious outlaw Buford "Mad Dog" Tannen (the great-granddaddy of the McFly family's manservant). In this scene, Marty is dragged behind a horse, then hanged from his neck until Doc Brown heroically saves his life.
Man, Michael J. Fox really pulls off that "I was just nearly hanged" look and voice at the end, doesn't he? Well, this was somewhat aided by the fact that he was seriously nearly hanged while shooting this scene. Most of the "Marty's almost killed" shots in this movie were done with a stuntman, but obviously they needed to show the actor's face at some point or people would ask for their money back, so for this sequence they had Fox stand on top of a box and put a noose around his neck.
Universal Pictures They tried a close-up of his face, but it looked like he was masturbating.
However, director Robert Zemeckis just could not get this to look realistic, so Fox offered to do it without the box, relying entirely on careful hand placement on the noose to keep himself from asphyxiating. This worked for a few takes, but on the third one, Fox missed his hand placement and was really strung up by his neck, like a common pig burglar.
Universal Pictures Fortunately, Zemeckis still had Eric Stoltz on speed dial in case they needed another Marty.