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 and filmed its death, is heard throughout the video, narrating the strange spectacle. “That is just crazy! How you gonna bite yourself, snake?” he shouts hysterically—or should we say, hiss-terically.

“You have your own tail in your mouth, buddy. Wow.” The viral video already has over 750,000 views.

To understand how these limbless, flexible reptiles are capable of movement up to an hour after their deaths, National Geographic got in touch with James Murphy, head of the Reptile Discovery Center at the Smithsonian’s National Zoo in Washington, D.C. (Also see: “Virus That Twists Snakes Into Knots Revealed.”)

What exactly is happening in this video? Is the snake dead?

By the time the snake has lost its head, it’s dead and the basic body functions have ceased, but there is still some reflexive action. In other words, snakes have the capability of causing biting and injecting venom even after the head has been severed, even though it is dead.

Why does it bite itself?

That’s what is available, that’s what is next to him. Even when you take the head off, a snake can continue to bite and open its mouth. This is why snakes sometimes bite themselves, especially when they get excited and they are not careful about what they are trying to bite.

Can a snake die from being poisoned by its own venom?

This is a debated topic. There are certainly cases of captive snakes biting each other and causing the death of another snake of the same species. But the question is whether this is because of injury from the mechanical bite—when fangs penetrate the body of the other snake—or from susceptibility to the venom.

If I find a snake in my yard, what should I do?

Avoid it and do not try to kill it. That is when most snakebites occur. From the perspective of a herpetologist, I don’t want to see any snakes killed. If people try to capture or kill a snake and they don’t have experience, they can get bitten themselves.

This interview has been edited and condensed.

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