Calum Von Moger is an actor and bodybuilder, who will be playing the role of Arnold Schwarzenegger in the upcoming film "Bigger." He's pretty active on Instagram, and posted up this video of him rapelling off a cliff with his brothers. Maybe Calum is a little too big to be doing this sort of thing? I don't know, but what I do know, is that if you turn up the volume, you can hear the exact moment his knee snaps. The "pop" is clear as day, and then his screams of pain. Hopefully, it's nothing too terrible, but from the sound of that snap, it can't be good.