This may be the ocean’s most horrifying monster (and you’ve probably never heard of it)

A rhizocephala bursting from the abdomen of a crab. Image source: wikipedia.

A rhizocephala bursting from the abdomen of a crab. Image source: wikipedia.

When I first learned about rhizocephalan barnacles I lost my appetite. I was taking a parasitology course, and even though I’d developed a thick skin, something about this insidious creature deeply disturbed me. Even now, the thought of one makes me shiver. I’ve never watched a movie monster, heard a fairy tale, or seen a video game with a villain more horrifying than this one. And unlike those monsters, this one is real. To understand the full terror of this monster, you have to put yourself in the place of another animal. These poor creatures are its victims, and you see them all the time. Imagine you’re a crab, and for full effect, imagine you’re male.

You’re lingering on the shoreline, the warm sun on your back, cool water in your gills. You’ve reached a large size, dodging the many dangers of youth. Life is going well. But today you begin to feel strange–maternal almost–as if there is something growing inside you, and in fact, something is.

Can you feel the roots of this monster creeping within? Illustrated by Haeckel. From Wikipedia Commons.

Can you feel her roots growing in your body? Illustrated by Haeckel. From Wikipedia Commons.

Its roots are crawling through your tissue, your gut, your brain. It’s a rhizocephalan barnacle, and it’s about to take you over.

Your new tormenter is a member of one of the strangest groups of animals known. The adult female body of the rhizocephalan is twisted and deformed, not resembling in any way its barnacle cousins living on rocks near shore. She has lost her hard shell, her legs, her eyes, and transformed into sickly yellow roots and sinuous twisting filaments that are slowly grow like black mold through your tissues. But she looked normal once: when she was young. As a juvenile she looked like a normal barnacle larva, only a few millimeters long. But her juvenile body had one terrible difference: her head was tipped with a needle protruding form her shell. When she found you, she used her body like a hypodermic syringe: stabbing you and injecting her own cells under your skin. All that’s left of her is now growing and spreading like a cancer through your system. You’ve stopped growing. Her fibrous tentacles are consuming your extra energy.

Just when it seems it couldn’t be worse, your abdomen explodes. You’re now sterile, and her gonads are erupting out from where your genitals are. Her tumorous ovaries now attract a male rhizocephalan larva, who injects his own cells into her. These grow into testicles within her body. She now has everything she needs for her next takeover.

But none of this bothers you now.  She has woven her threads through your brain. She’s been secreting chemicals to control you–you’ve forgotten who you are. You now believe you are female, and the bulge in your abdomen is a brood of your own eggs. Moreover, you are about to give birth. You care for and clean these eggs, as if they were your own.

One fateful evening, you feel a powerful impulse to move to the shallows and spawn–releasing your new young into the ebbing waves. Your body is now hard, deformed and feminized. Despite all this you look into the sea, grateful that you’ve created a new generation. Your bliss uninterrupted by the reality that you have now released an infection that will spread, perhaps to your brothers, your mother and your children. But any piece of you that might mourn for them is gone, or perhaps if there, unable to stop what you’ve become. You are a shell for a rhizocephalan now, basking under the watery moon and stars.

RR Helm (30 Posts)

I am a PhD candidate studying jellyfish development and evolution at Brown University. I've participated in numerous research expeditions, studying jellies all over the world, from Africa to the abyss. I am currently studying the beautiful mauve stinger jellies, found in the Mediterranean, and the ghostly Atlantic stinging nettles found on the US east coast.





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106 comments on “This may be the ocean’s most horrifying monster (and you’ve probably never heard of it)
  1. Pingback: This may be the ocean’s most horrifying monster (and you’ve probably never heard of it) | Rocketboom

  2. freaky, awesome,especially scary if one stops and thinks of future genetic experiments for the “betterment”or “protection” of mankind. BBRRRRrrrrr!

  3. freaky, awesome,especially scary if one stops and thinks of future genetic experiments for the “betterment”or “protection” of mankind. BBRRRRrrrrr!

  4. Pingback: Fact really can be far stranger that fiction – rhizocephalan barnacles « Skeptical Science

  5. «I’ve never watched a movie monster, heard a fairy tail, or seen a video game with a villain more horrifying than this one.»

    I believe most fairy tails are mostly silent. I think they have something built into their structure which suppresses sound production during flight (much like owl flight feathers).

  6. Wonderful creepy description of rhizocephalans! I’m studying a rhizocephalan that infects king crabs in Alaska. They are so amazing and we know so little about them!

  7. Wait… I made this up for a D&D game 15 years ago, psionic beasties I called limpet minds. And now you are telling me they are real?!? Arrrgghh!!!

  8. Dear God! Why is this not in a horror novel? All I could think of when I was reading this was how similar it is to the ‘Alien’ movie (abdomen rupturing). Kudos, it is very well written!
    Does the rhizocephalan only infect intertidal crabs?

  9. Am I the only one wondering what they taste like,and if by chance I’ve already eaten one by mistake….

    Can’t sleep barnacles will eat me!

    -C

  10. It’s only a mater of time until a human version either genetically mutates or gets engineered… wait, isn’t it called government?

  11. Am I a little screwed up in being surprisingly not horrified by this? The entire description sounds like you’d be thinking “oh hey, cool, things are going great!” because crabs don’t (to the best of my knowledge) have a strong sense of past or critical thinking. If it feels like it’s going good, then good. This is only horrific from an outsiders perspective, the crabs seem like they’re pretty hunky-dory. They just aren’t making new crabs anymore, despite what they think. Then again, we have no idea how they actually perceive this… I think we might be making a bit of this crab’s perspective up.

    • Sercee – You are completely right. And I’m with you. A crab isn’t going to have any comprehension of anything this article is concerned with and they don’t have pasts or presents to mourn, so it’s not really scary or sad.

  12. It’s like the Cordyceps fungus with insects!
    Except that fungus is something way more primitive than that…

  13. …Under what pressures and or circumstance did these barnacles adapt these traits? Very interesting! Science fact is usually better than science fiction! Great story!

  14. Quite a normal outcome of evolution, but from a creationist perspective it makes God seem like a pervert.

  15. “Rhizocephalans can infect a variety of crustaceans, including hermit crabs, shrimp and prawns, so not just intertidal.”

    So..would the Mantis Shrimp be one of them? Because that’s just asking begging to be put in the sequel of this nightmare you’re brewing.

  16. I think you mean a “fairy tale”, not “tail”, unless that is another horror story you are not telling us?

  17. I’m so glad I don’t eat shellfish…. but do these affect any other life forms other than Crustaceans, like larger fish or aquatic mammals?

    • As far as I know they only infect crustaceans… large fish and aquatic mammals have their own horror stories ;)

  18. Pingback: I’ve Got Your Missing Links Right Here (26 October 2013) – Phenomena: Not Exactly Rocket Science

  19. I think I lived with and almost married this fish, but I found my oysters and cast her back in the sea just in time

  20. I’m wondering who will make a movie about this thing but substitute human males as the hosts. That would be interesting!

    • I’ve often fantasized about a Sci-Fi movie along these lines. Mostly they involved aliens, probes and a genetically engineered virus doing pretty much the same thing to breed a human being based food supply for traveling alien ships replenishment.

  21. Seems to me you are talking about a religious extremist?

    “Your bliss uninterrupted by the reality that you have now released an infection that will spread, perhaps to your brothers, your mother and your children. But any piece of you that might mourn for them is gone, or perhaps if there, unable to stop what you’ve become.”

    • wow, calling everyone out… but if you really think about it, if there were no poor just rich and richer and no tax on anyone do you think there would be any Political parties? I dont… when time comes imma be in an independent party but as for now my family is democrat and from what i see the republicans are just bitching about nothing… obamacare i dont know much about but honestly its for the nation’s betterment so please calm down, its not that serious

  22. AS a poet and aspiring writer i will use this to write a story scyfy style and also for character development on a separate project… if there is something the populace wants specifically just tell me by replying under this. All suggestions will be used

  23. Pingback: The Ocean’s Most Terrible Parasite | JewishProblem.com

  24. I wonder if any of those “Brood-crabs” were ever caught and served up at “Red Lobster?”

  25. Pingback: This May Be The Ocean’s Most Horrifying Monster (And You’ve Probably Never Heard Of It)

  26. Pingback: No matter how bad you are

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