The famous New Jersey beaches are no stranger to odd creatures. Visitors have spotted everything from humpback whales to UFOs . . . and, of course, the cast of MTV’s Jersey Shore. But the latest New Jersey beach sighting has even the experts baffled.

Strange, bright blue “jellyfish” (the likes of which Jersey residents have never seen before) recently began washing up on the sand. Locals were initially wary of the turquoise blobs—but as it turns out, they’re mostly harmless.

So what exactly are these tentacled creatures? And how did they get here?

Polyps, Not Jellyfish

The blue button (or porpita porpita) isn’t actually a jellyfish at all. It’s a Hydrozoa, or a colony of polyps connected to each other through a series of tube-like channels. According to marine biologist Paul Bologna, the polyps “come together to create a super beast“—each small cluster within the creature plays a different role, like reproduction, nutrition, or protection.

You may not be familiar with the blue button, but you’ve almost certainly heard of his bigger, badder cousin, the Portuguese Man O’ War. The Man O’ War can deliver a sting powerful enough to take down a human—and while the button isn’t nearly as tough, it is venomous. Similar to most jellyfish, touching a blue button might leave you with a slight irritation or mild rash.

The stringy appendages, which hang off the round “button” part of the blue button, are used to stun prey. Oddly, they are not actually tentacles, but rather hydroid colonies. Each strand is made of numerous branchlets, each of which ends in a tiny knob of stinging cells. The button itself is filled with gas and keeps the creature afloat.

How Did They Get Here?

After spotting the first button last week, Holly Horner of Egg Harbor, New Jersey, said, “It’s not something I’ve ever seen here before, and I’ve been walking down that beach since I was 10-years old. I’m 55 now.” In fact, it doesn’t appear that anyone has ever spotted a blue button in NJ before.

Unlike real jellyfish, the blue button can’t swim—they just float on the surface, moved along by the ocean current and the wind. It would take enormous water pressure to move them very far.

In this instance, experts believe that Hurricane Florence pushed them, and several other species of warm-water jellies, out of the Gulf Stream and up the coast towards New Jersey.

Will They Stick Around?

Bologna stated that he’s seen blue buttons off the Florida coast but never in New Jersey—and he doesn’t expect them to survive in the Garden State for very long.

The tiny predators mostly live in saltwater, and typically in sub-tropical and tropical waters (like the Gulf of Mexico or the Mediterranean Sea), which is why it was so shocking to see them show up on a New Jersey beach.

Unfortunately, they will likely all die off as the water temperatures drop.