You probably think you know everything you need to about worms. They're just wiggling tubes of flesh with indistinguishable asses and faces that commit suicide on sidewalks during rainstorms. All caught up. But the benign worms you're used to seeing speared on fishhooks and fried up in children's literature are only a tiny percent of all the species of worm out there. And when we say "out there," we mean "crawling free of the bowels of hell as we speak."
At over 10 feet long, bobbit worms are about the closest thing we have to the sand worm in Dune. They have toxic bristles up and down their body that can cause permanent nerve damage to anyone who touches them, and they feed by grabbing their prey with massive, strong jaws and sucking it down into the sand.
They are ambush predators that wait in shallow waters with only about a tenth of their body poking out of the sand and their mouths stretched completely open. As soon as one of their antennae detects something in the water, they lunge for it, even if it's significantly bigger than they are. Their strikes, it should be noted, are so powerful that they'll sometimes accidentally just cut fish in half while trying to grab them. So don't be fooled by the fact that, up close, it's the iridescent color of a middle school girl's Trapper Keeper.
Dante's Inferno would have been so much scarier if he'd known anything about the ocean.
To get a sense of how horrifying these worms are, at Newquay's Blue Reef Aquarium in the U.K., they couldn't figure out what was eating all their fish each night. They set up traps with fishing line and hooks, and each morning the lines were snapped and the hooks and bait were gone. After taking the aquarium apart, they found a massive bobbit worm in the sand that had apparently just been digesting the hooks.
Oh, and the bobbit worm, just like us, prefers warm, shallow waters. So we're probably going to have to let them have the good beaches for now.