http://www.youtube.com/watch?v=7C8UqgVK4EI They say karma comes back to bite you in the butt. For the wild copperhead snake in the above YouTube video, it wasn’t karma that bit his behind. It was his own decapitated head. The video uploaded Tuesday shows a severed copperhead snake head resting idly next to its slithering, beheaded body. At 26 seconds, just when you think the serpent is as good as dead, the detached head surges up and sinks its fangs into its own tail. (See more snake pictures.) Sam Billiter, the Huntsville, Alabama, man who killed the animal