A small isopod scurries along the ocean floor, collecting food.
It can see above it there are no predators, so its scavenging mission can continue without
danger.
There is nothing below it except the sand of the sea bed.
Or so it seems.
Suddenly, the sandy floor seems to explode, and a monstrosity bursts forth.
A long snaky worm-like creature with extended antennae and a segmented body extends from
its burrow and lightning-fast, grabs the isopod in its jaws.
Just as fast, predator and prey sink back into the sand, never to be seen again - at
least until the hunter is hungry again…
Something out of a horror movie?
Not quite.
It was the beginning of 2021 when Ludvig Lowemark, a scientist from National Taiwan University,
announced that he and his fellow geoscientists had made a disturbing discovery in the sea
beds.
It was a creature that was one of the ocean’s deadliest predators twenty million years ago,
but it wasn’t an ancient whale or shark, or a giant squid that wrapped unsuspecting
prey up in its tentacles.
It was a worm.
But definitely not like the earthworms you see in your garden.
We don’t know as much about these ancient forms of life as we’d like, because fossils
usually require one thing to be left behind - bones.
And that makes studying invertebrates tricky.
But this mysterious worm, named Pennichnus, had a few factors that made it different from
most invertebrates.
For one, it had an exoskeleton that was more likely to be left behind and survive in fossils.
Second, it had distinctive burrows that were easy to be identified in the rock that was
preserved.
Finally, it was big.
Really big.
So, how big can a worm get?
Ludvig Lowemark and his team believe Penninchus could have grown to be as large as six feet
long or larger - making them a threat not just to unfortunate fish or isopods that wandered
by, but to larger prey - including humans if they happened to be around.
However, these creatures weren’t easy to find.
They were likely masters of disguise, and functioned less as apex predators on the hunt
than as living deathtraps waiting to be triggered.
People have compared them to a pair of iconic monsters from science fiction - the Sarlacc
Pit from Star Wars and the Sandworms from Dune - both of whom lay in wait in the sand
until their prey came into range.
But Penninchus may be more vicious than either of them.
The scientists carefully reconstructed the creature’s burrow from samples of rock found,
and nearly complete fossils were found inside.
The creature would lurk inside, completely concealed except for one part of its body
- its long antennae, that it used as feelers.
These sensors would alert the creature to when an unfortunate sea creature was passing
in range, and like a loaded spring it would burst out of its burrow.
This is similar to the trap system used by an iconic plant - the Venus Flytrap, which
snaps shut when it senses movement.
But unlike the hungry plant, Penninchus had one advantage.
It could fight.
And when it got prey in its jaws, it didn’t back down.
When Penninchus latched onto its prey, the fight was just beginning.
The monster worm would recede back into its burrow, but the grabbed creature would still
be alive.
There would often be a pitched battle under the sand, as the creature desperately tried
to escape and the worm clamped down tighter to finish it off.
This often led to distinctive markings around the burrow from the disturbances - but it
was likely that most if not all the battles ended with a Penninchus with a full belly.
But what would happen if the creature bit off more than it could chew?
While we don’t have many fossils to indicate this, Penninchus seems to be built in a way
that would allow it to be very flexible.
That means it wouldn’t be vulnerable to a larger prey snapping it in two, and it has
no bones to break.
If it was in a pitched battle that it was in danger to losing, the odds are it would
simply release its powerful jaws and let its prey swim or scuttle away - if it was in any
shape to do that after the initial bite.
Live and attack another day.
There’s bound to be something swimming by soon.
But what if Penninchus had to go after Earth’s dominant lifeform today?
At six feet, Penninchus is longer than many humans - and could definitely pose a threat
to us if it existed today.
There’s just one problem for the monster worm - what would it do with us?
While it may be close to us in length, it’s definitely not in overall size, and definitely
wouldn’t be able to eat us.
But that doesn’t mean encountering them would be a pleasant experience.
Humans walking along the sea bed could definitely trigger its antennae, and between their speed
of attack and powerful bite, they could definitely cause some serious damage.
The effect might be similar to the Mantis Shrimp, another sea-bed predator that punches
above its weight class.
This crustacean kills by delivering a devastating high-speed punch with its leg.
The impact is so powerful, the creature gained the nickname “Toe-Splitter” - with many
of its victims needing surgery.
The good news is, Penninchus is extinct and humans aren’t likely to encounter it - right?
Yes...and no.
We only have a few fossils of this ancient sea worm and some fossilized burrows.
So how do Dr. Ludvig Lowemark and his team know so much about how it lived and hunted?
It’s because there is a creature living today that may be a direct descendant - and
while it may be smaller, it’s no less dangerous and terrifying.
Eunice Aphroditois is a benthic bristle worm that lives in warm ocean waters, but is much
more known by its more colorful name - the Bobbit Worm.
Named after the famous case of Lorena Bobbit, who hacked off her abusive husband’s...member
in 1993.
What’s the connection between this worm and that case?
Well, the worm’s vicious snapping motion made people think it could take off members
in a hurry.
Could that happen?
Probably not - but no one’s looking to find out.
Typically living among coral reefs, this modern worm can be as small as four inches - but
the biggest and most well-fed specimens can grow to as much as ten feet.
Despite this long body, it’s still very thin - only an inch wide at most.
With no eyes, it hunts entirely using its antennae as feelers and has a similar hard
exoskeleton to the ancient version.
While it’s not known if Penninchus had similar features, this creature has retractable mandibles
that are strong enough to snap prey clean in half.
And just like its ancestor, it’s a master of disguise.
The Bobbit Worm became famous in 2013, when an aquarium’s staff noticed something disturbing
in their fish tank.
The collection of coral seemed to be getting smaller and smaller, almost like something
had been eating it.
After observing the tank carefully for a while, they saw something moving in there - something
that shouldn’t be there.
The Bobbit Worm had likely hitched a ride back when it was tiny, and had been growing
fat on the tank for years.
By the time the aquarium staff finally noticed it, the creature had grown to over four feet
in length - and it was going to keep growing as long as it had things to eat in the tank.
But one detail indicated just how much of an invasive threat these worms could be.
The long creature covered in small spiked tentacles seemed to move as one, but before
the surveillance video that had discovered it started, its tail had been cut off.
And before the footage of the worm ended, the tail seemed to slither away independently
- indicating that each segment of the worm could potentially become its own creature.
And when the worm is as hungry and as deadly a predator as this one, that could be a major
problem for any bodies of water it swims in - both as small as a fish tank, and as large
as a sea.
But some scientists worry that the creature may have another deadly weapon in its arsenal.
When the Bobbit Worm became world-famous in 2013, everyone wanted to study the four-four
creature they nicknamed “Barry”.
A newspaper quickly claimed that the worm likely had a devastating venom in its bristles
- possibly causing permanent numbness and paralysis in humans who touch it.
But scientists studying Barry raised doubts - the theory about the venom came from assessing
another family of worms called fireworms that have bristles capable of causing severe skin
irritation.
However, the bobbit worms seem to be something very different despite some physical similarity
to fireworms.
And possibly far more ancient.
The bobbit worm can cause a lot of havoc in fish tanks, but it’s far more dangerous
to the creatures it encounters in the wild.
It has a wide range, living in sandy and muddy areas near coral reefs.
But it’s notoriously hard to detect due to its ability to blend into its surroundings
and its habit of burrowing into the ground.
It can live deep under the water - as deep as 285 feet.
And while most of its prey never see it coming, a few fish have developed a unique defense
mechanism.
A group of fish swim over the sea bed.
Suddenly, the worm strikes, grabbing one of them.
But the other fish don’t swim away and leave their schoolmate to its fate.
Instead, they mob the worm, shooting the worm and its burrow with jets of water from their
mouth, hoping to disorient it and make it let the other fish go.
Does it work?
Not always, but it gives them a fighting chance - and proves that in nature, few creatures
are without some kind of defense.
But has this nightmare worm really been stalking the seas for twenty million years?
It’s too early to tell if Eunice Aprhoditois and Penninchus are the same creature, but
they’re likely closely related.
A look at the Bobbit Worm’s reproductive cycle indicates they can live three to five
years, but their eggs have a harder go of it - often being eaten by other animals before
hatching.
Which may be the only time the nightmare worm is prey rather than predator.
How big would Penninchus grow?
What were the biggest animals it hunted in ancient times?
The life cycle of its modern relative may provide some clues, but for now, the ancient
nightmare worm found in the seas off Taiwan is keeping many of its secrets locked up in
the past.
And most people are probably happy they won’t be encountering it any time soon.
For more on nature’s deadliest small predators, check out “Murder Hornet Sting, This Is
How Painful It Is”, or watch “Most Venomous Animals In The World You Should Watch Out
For!” for some of the animal kingdom’s secret killers.