Confession: I suffered from a childhood fear that my body would turn inside out. Either some external force would evert me like a used sock puppet or my body would just up and reverse itself. Either way, my unease was palpable, and it all traces back to the 1979 film Screamers.
I mean just look at that VHS cover! I was 8 years old when I first saw that on the shelf of the local video store. And since my family didn’t rent horror, it was decades before I found out that ABSOLUTELY NO ONE turns inside out in this film.*
*Worse still, it seems that the distributers actually filmed a gruesome man-turns-inside-out scene for the U.S. trailer but didn’t add it to the film itself. Audiences went ballistic. BadMovies.org has lots of great info on this film right here.
But ever up to the challenge, my 8-year-old brain cooked up its own terrifying visions of blood-spurting inside-out men. I imagined doctors powerless to reverse the condition. A few years passed before I actually stopped to ask if total body eversion were even possible—or why the inside-out man from Screamers has blue jeans on.
Science vs. Inside Out Men
So can the entire human body turn itself inside out? Not really. Our bodies just aren’t that pliable. Plus, they consist of various systems and internal structures. You can turn a tube sock inside out, but even an earthworm’s tubular body would tear apart before you effectively could evert it.
However, the animal world is full of inside-out examples related to individual organs or parts of the gastric system. Take bladder eversion for instance. It’s rare in humans, but you’ll find it in cows and horses from time to time. In these instances, the bladder extends from the body cavity. This is called prolapse, and it occurs with other organs as well.
If you’re like me, the thought makes you cringe. Yet countless animals have evolved to depend on eversion as part of their daily routine. If you’ve watched Life on BBC or Discovery Channel, you know that sea stars evert their stomachs when they feed. Nemertine worms also have a ghastly eversion feeding method: They turn their proboscises inside out. Click here for some footage.
Hang out with rays and sharks enough and you’ll likely witness an equally grotesque habit known as full gastric eversion. When humans need to empty our stomachs in a hurry, we vomit. Rays and sharks just turn their stomach inside out and flop it out their mouths. It’s a lot like turning your pockets out to get rid of some lint. And yes, there’s a video:
And then there’s the vampire squid, which uses eversion to ward off predators. It simply flips its webbed array of arms back over the rest of its body. Imagine if you could pull your top lip back over the rest of your face and your bottom lip over your chin—and then kept tugging till you were covered in a gleaming, pink cloak. It’s the same principle, but it’s not full-body eversion.
Horrible Accidents & Guts
Okay, so a body won’t totally evert itself, but couldn’t some horrible accident turn you inside out? Nope, don’t worry about this one either. Even rapid decompression, which does all sorts of impossible damage to bodies in films, couldn’t pull it off. U.S. Army experiments on salmon indicate that rapid decompression (such as in a ruptured airplane fuselage or spacecraft) can result in stomach eversion, but no inside out fish.
You’ll find accounts online (and in that one Chuck Palahniuk short story) about catastrophic injuries involving swimming pool intakes, but the human body still wouldn’t turn inside out. We just aren’t pliable or rugged enough for that to happen. Heck, as Neil deGrasse Tyson likes to point out, even the unimaginable pull of a black hole would merely slice you into a bazillion tiny pieces and extrude you through the fabric of space:
I suspect other kids were similarly traumatized/inspired by that Screamers cover. Just look at the “fog that turns people inside out” from The Simpsons, Nickelodeon’s Inside Out Boy, or the scene in Invader Zim where Dib winds up reversed into a throbbing slab of guts. The list goes on.
The inside out men still show up in my dreams sometimes, but that’s about the extent of it.
Robert Lamb is a senior staff writer at HowStuffWorks.com and co-host of the Stuff from the Science Lab podcast and blog. He is also a regular contributor to Discovery News, where he strives hard to work Texas Chainsaw Massacre references into solar physics articles.
