This story is from The Pulse, a weekly health and science podcast.
As a kid growing up in southern California, Don Arndt always loved the ocean.
“I’ve always been fascinated with fish,” he said. “My dad was a scuba diver, and he started me scuba diving when I was 9.”
Over the years, that fascination bloomed in a number of directions — scuba diving, fishing, fishkeeping. He eventually moved away from the coast. But as an adult living in the Midwest, Arndt continued his passion with an expensive and elaborate hobby: a 150-gallon saltwater aquarium that’s built into the wall between his garage and his family room.
“The aquarium itself sits in the garage in a closet, but there’s a hole cut in the wall, so it looks like a picture on our wall,” Arndt said.
The tank, which Arndt set up in 1996, is huge — 4 feet by 2 feet by 3 feet — and packed to the gills with interesting marine life, ranging from coral and sponges to exotic tropical fish. It’s a lot of work, but Arndt says it’s worth it.
“It’s a way for me in Michigan to experience a tropical reef any time I want to,” he said. “It’s very relaxing.”
At least it was relaxing — until one night in 2009, when Arndt spotted something strange.
The enemy emerges
“I noticed one night that one of my corals, something bit a big hole in it and scurried off into the rocks,” he said. “And that’s how this whole sort of nightmare started.”
At the time, not many people knew about Bobbit worms — but what they’d heard was bad. For one thing, they’re hideous.
“A Bobbit worm looks like a giant centipede,” Arndt said. “I more liken it to the sand creatures in ‘Dune.’ It looks just like that. So it’s got these tentacles that stick out and it’s kind of multicolored. It’s quite disgusting.”
They grow incredibly fast — and incredibly long.
“They can grow to 11 feet long,” Arndt said. “This particular one that I had was about three-quarters of an inch around.”
They’re also ambush predators. They burrow into the sand and then shoot out with razor sharp jaws capable of slicing fish in half.
“The thing could disappear in a fraction of a second, they’re so fast,” Arndt said.
Worst of all, they’re destructive.
“They literally eat everything,” he said. “I observed him one night eating stony coral, which is basically calcium, like an ear of corn. He was just chewing it right off. They eat fish — they eat everything.”
One of the things that was most disturbing to Arndt was that the worm had likely been living in his tank for more than 10 years by the time he noticed it.
His theory on where it came from: the live rock that he’d installed in his aquarium back in 1996.
Live rock is rock or fragmented pieces of coral that are sold to aquarium owners straight from the ocean. They’re desirable because they can introduce a variety of bacteria, algae, and tiny creatures into saltwater tanks that help filter the water and create a healthier ecosystem. Of course, in Arndt’s case, it had also brought a Bobbit worm.
Arndt was guessing that the worm was likely a baby when it first hitched its way into the tank. Thirteen years later, it had grown, he estimated at the time, to around 2 or 3 feet — all of which it was able to hide, slinky-like, in a 1-inch hole in the aquarium’s live rock.
Arndt had no idea how to get the worm out of the rock it was living in — and there was no way to get the rock out of the aquarium. It weighed 90 pounds dry — soaked with water and covered in coral, Arndt says, it probably weighed close to 300 pounds. Besides that, it’d become an integral part of the tank’s ecosystem.
“There was just no way to get it out without totally destroying the whole aquarium,” he said.
No one else Arndt talked to knew what to do either — so instead, he turned to an ancient tome of wisdom: “The Art of War.”
That’s right — the famous military treatise written in 5th century B.C. by Sun Tzu, source of the famous quote, “Keep your friends close, and your enemies closer.” So, Arndt decided, he would start off by befriending the Bobbit worm.
“So I started feeding it, trying to feed it every night,” he said. “They’re nocturnal mostly, and I would stay up all night waiting for it to stick its little head out.”
Arndt fed it shrimp with a pair of tongs — every night at the same time — to earn the worm’s trust.
“And then,” Arndt said, “I started the war.”
Attack No. 1: Testing the worm’s ‘metal’
Arndt’s first plan of attack was a plot worthy of a Shakespearean drama — he would poison the worm.
“Once I got it eating shrimp, I would inject the shrimp with copper, which is poison to most aquatic animals,” Arndt said. “And then, hopefully, it would die.”
So Arndt injected the shrimp with liquid copper, and lowered it into the tank. He did that for several nights.
So what happened?
“Nothing,” Arndt said. “It just kept coming back for more.”
Attack No. 2: De-worming the worm
Arndt moved on to his second scheme: Interceptor, a deworming pill for dogs that is also used to get rid of aquarium pests.
One pill was enough to de-worm his 109-pound German Shepherd, so Arndt figured half-a-tablet should do the trick. So for three nights in a row, Arndt fed the worm shrimp stuffed with Interceptor.
“He kept coming back every night,” Arndt said. “He was getting bolder, which I was also encouraging, like pulling it out a little bit further to see how far — at this point, I didn’t know how big he was.”
If the worm was long enough, Arndt was hoping, maybe he could lure it out far enough to seize it with the tongs and yank it out.
“And then I did some reading and they said, if you break it in half, you will have two because it’s a segmented worm, so it’ll grow a new head,” he said.
So that was a no-go — as was tack no. 2, the deworming pill.
“So then,” Arndt said, “I got really creative.”
Attack No. 3: Starvation by superglue
Onto Arndt’s third plan of attack — a shrimp filled with superglue.
“I thought if it ate it, it would glue its mouth closed,” he said. “So I literally hollowed out a shrimp shell and filled it full of superglue and fed him that.”
After the first night, Arndt thought he had him. The worm ate the superglue shrimp, and then disappeared for a couple days. But pretty soon, he was back — popping out of his rock, opening his horrible maw for more superglue shrimp.
“He came back every night,” Arndt said, “I think it was four or five times that I gave it a try. It still didn’t work.”
Attack No. 4: Eat glass, punk
By this time, Arndt was getting desperate. In addition to his own morbid experiments, he’d turned to an online aquarium forum for help, and his posts generated a lot of interest. They’ve since become legendary under the name “The Bobbit Worm Chronicles.”
Arndt says he thinks a lot of the interest was because this was a relatively new phenomenon — a problem even some professional aquariums hadn’t cracked yet.
“Plus, the thing is just so disgusting,” Arndt said. “It’s like watching a car crash.”
It was also a delicate problem to solve. Anything that could kill the Bobbit worm could potentially kill Arndt’s other fish. He’d taken a risk with the liquid copper and the Interceptor pills. He couldn’t just grab the worm because it was so cautious – it would only come out of the rock partway — and even then, only long enough to eat, before it darted back into its lair.
Arndt needed something that would physically kill the worm, not just poison it. Everyone on the forum had their own ideas.
“Someone on the thread suggested glass, so I ground up glass, mixed it with superglue, and put it in there,” Arndt said. “I think the second time I fed him shards of glass — like, quarter-inch shards of glass.”
Arndt even added some more Interceptor pill for good measure.
Ding-dong, the witch is dead … or is it?
Forty-eight hours after the first glass feeding, the Bobbit worm was nowhere to be found. Arndt was ecstatic — he claimed victory on the message board: “Ding dong the witch is dead!” he wrote. “I tried to feed a regular shrimp outside her door, and nothing … that’s a first.”
He posted again the following day, and the day after — each time celebrating what he hoped was the Bobbit worm’s death.
And then, on the sixth day, came this post: “$#!^ he is still alive! He was out during the day this time. maybe he is sick, you know kind of like the rabid skunk. I guess I’ll try the super glue again. 5 nights I thought for sure I had him.”
Not only that — the Bobbit worm was back to destroying Arndt’s aquarium; he’d spotted it eating one of his corals.
At this point, Arndt was desperate. He was about three weeks into his war against the Bobbit worm — and he was starting to lose it.
“I was traumatized,” he said. “I was mad and frustrated that I couldn’t get the thing out. I wasn’t sleeping at night because I would have to get up at three in the morning to feed the thing every morning. I was just … very frustrated. Extremely frustrated.”
The Bobbit worm wasn’t just a nuisance — it posed an existential threat to Arndt’s aquarium. It was decimating his beautiful coral, and he worried that soon, it would start eating his fish — some of which he’d had for more than 10 years.
Arndt had been driven to the edge of his sanity. He’d been staying up half the night for weeks guarding his tank. He’d fed the worm liquid copper, de-wormer, superglue, and broken glass, all with no effect. Clearly, he needed to do something drastic – go to hand-to-hand combat with the worm.
“I finally was like, OK,” he said, “I’m just going to fish this thing out like it was a fish.”
Attack No. 5: Reeling it in
So one night around feeding time, Arndt baited a fishing hook with some shrimp, and lowered it into the tank.
“He swallowed it whole,” Arndt said, “and I had him.”
Arndt was a seasoned fisherman — but he’d never experienced anything like this.
“I mean, I’ve fished off the Florida Keys,” he said. “I’ve had some epic fish battles — but this one went on for like 40 minutes.”
At this point, it was 2:30 a.m., and Arndt was standing on top of his tank in his garage, trying to pull the Bobbit worm out. At the time, he had speculated that the worm was maybe 2-3 feet long — but as it kept unfurling, he realized that it had reached horrifying proportions.
“Every time I pulled, it would come out a little bit and it just kept coming out,” he said. “It was kind of disgusting.”
The worm was strong, but Arndt was stronger. And then, suddenly, it happened — the Bobbit worm snapped. Arndt stumbled backward. He watched with horror as the remaining section of the worm darted back into its rock.
“And I was left with a 2-foot section of brown grossness,” he said.
He watched as the section wriggled around on the floor, before bagging it and throwing it away.
The worst part? Somehow, Arndt had ended up with the back end of the worm.
“Like, I looked at it and I was like, ‘Oh, there’s no head,’” he said. “How did I catch the back end?”
Arndt posted a picture of the section he’d caught on the forum and wrote, “I don’t know what happens now but there is no sign of him. I am so grossed out I can’t sleep. He is far grosser in person. Yuck. Maybe I got enough that he will die or maybe he needs to heal and will be out looking for food tomorrow … I don’t know. For now I won the first battle. Now I have to get the rest!!”
Attack No. 6: The Bobbit’s mistake
Clearly, Arndt had injured the worm — but he also knew Bobbit worms are capable of regenerating; plus, it still had his head. So for the next few days, he kept watch.
A day went by — then another, and another. A week. Ten days. Arndt tried holding out some shrimp for the worm — still nothing. Maybe it really had died.
Arndt was just starting to relax, just starting to accept that maybe this whole hellish journey was finally over … when he spotted him.
“I saw him in the middle of the night, eating a very beautiful, bright blue sponge that I had,” he said.
Arndt watched with rage as the Bobbit worm chomped away at his sponge. But then something lucky happened — the worm left his usual hideout, the giant rock, and crawled into a smaller one. Arndt knew that this was his chance — maybe his only chance.
“And I pulled that rock out, dragged it out of my driveway at 3 in the morning and started busting it up,” he said. “First, I tried spraying hot water inside its hole to see if it would come out. It did not. So I picked up the rock and broke it. And then it came crawling out — all 5 feet of it.”
Remember, Arndt had already snapped off another 2 feet of the worm — which meant, at one point, it measured around 7 feet long.
“I believe I swore and then was jumping for joy and trying to take videos of the thing,” he said.
You’d think, after everything the Bobbit worm put Arndt through, he’d want to destroy it right then and there — but he didn’t. Instead, he chucked it in a bucket full of water, and the next day called a friend who worked at the local pet store. He told Arndt to bring it in.
After everything they’d been through, was there any part of Arndt that had developed an affinity for the worm? Maybe, even, affection?
“Yeah, a little bit, maybe — maybe,” he said. “I guess maybe that’s why I didn’t kill it right away. Plus, I didn’t know how to kill it, to be honest. I mean, this thing had just survived everything I could think of.”
The Bobbit worm lived for a while on display at the pet shop — a warning to other aquarium owners of what might be lurking in their tanks.
“I did go look at it a few times,” Arndt said. “He didn’t recognize me.”
But despite his disgust and hatred for the Bobbit worm, Arndt couldn’t help but marvel at it. The worm was now living in a small tank populated by several 3-4-inch rocks — a serious downgrade from its previous digs. Even so, the 5-foot worm still managed to curl up and hide inside the small rocks.
“I don’t know how it did it,” Arndt said. “They’re an amazing creature, that’s all I can say. They will be around long after us.”
But the worm didn’t end up staying a de facto pet — in the end, they put him in a jar full of formaldehyde, and gave him to a local biology student.
Arndt’s aquarium has been fine ever since. All that’s left of this encounter is the forum thread – and Arndt’s memories of his epic war with a creature from the deep.
“This was a battle,” he said. “But I won.”