Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
A guy goes behind a rock and drops his pants to go to the bathroom then bends over and sits on a cactus. Then he hears a rattlesnake rattling, turns around and sees one. He yells and tries to run away with his pants around his ankles, screaming that a snake bit him. He demands that his friends suck out the poison from his rear end, but they hesitate, for obvious reasons. Finally one of them takes a look and pulls out the cactus spine.