Their feet came out of the water burning, stinging, itching.
Three anglers were wading in the sand bottoms of the Cape Romain National Wildlife Refuge recently and might have run into a bloom of jellyfish larvae, also known as "sea lice."
If it wasn't sea lice, it might have been baby jellyfish. Neither can be easily seen and both can sting.
Either way, it's a wake-up call for South Carolina as the summer bathing season picks up and venomous stuff is floating out there, particularly with the warm southerly winds moving in.
"Each year there's different stuff. It's kind of hard to tell what's biting you," said Folly Beach surfer Annie O'Brien, who paddled into a sea lice swarm of her own three or four years back.
The anglers ended up with hundreds of a swollen, mosquito sting-like bumps that tormented them for days. They did not want to be identified, but one of them described it as pure torture.
Surfer Will Schmieding of James Island swam into a swarm of sea lice in Costa Rica.
"All of a sudden my entire lower half was extremely itchy, and it got worse when I got out of the water and I was sitting at the bar and just wiggling around in my seat because it was so itchy. It only got better when I finally rinsed off,” he said.
Sea lice stings have not been seen so far by Charleston County Park and Recreation Commission lifeguards or by staff at Medical University of South Carolina or Roper St. Francis Healthcare. But if the anglers-in-misery ran into a bloom, they won't be alone for long.
"Usually when it's sea lice, a lot of people will feel it," said Luciano Chiaverano, a research scientist at the University of Southern Mississippi who specializes in studying jellies in the ocean.
Sea lice and baby jellies aren't as widely known as other stinging scourges of the beach — behind sea nettles, sea wasps, stingrays and the extremely painful Portuguese man-of-war. Unlike the others, though, keeping an eye out for these two won't do much good.
The baby jellies are translucent and only about the size of a quarter. The sea lice are only as big as fleas, said local kiteboarder Shea Gibson.
"They will stick like tiny barbs to your skin."
Tiny pieces of broken away jelly tentacles also float in the surf unseen and can sting.
Sea lice thrive in hot, salty water and are abundant in the Caribbean Sea, Chiaverano said. Blooms are far more common along the Gulf of Mexico beaches, but occasionally show up on the South Carolina coast. Gibson has seen them as far north as Virginia Beach, Va., he said.
The stings tend to show up on the more sensitive areas of the skin. Gibson said the worst is when it gets in the swimsuit.
The anglers likely had somewhat allergic reactions to the stings. For most people it won't be so bad and will ease after a few hours. O'Brien described it as uncomfortable.
Treatment is the usual protocol for jellyfish stings: a rinsing shower with soap to scrub away barbs, anti-itch lotions and anti-inflammatory medicine.
Meanwhile, be warned.
"It's summer. It's likely there are sea lice in the water," Chiaverano said.