there was an episode of Rifleman in the 1960s where the main character spends the night alone, camping out in an arid-looking area - dust and cacti. He opens his eyes the next morning and sees there's a rattlesnake coiled on his chest for warmth. The whole episode is spent with him holding very very still and sweating a lot. I don't remember the ending, but the actor does survive to make another show for the next week....