What's wet and gooey and stings like heck? These days it could be a trip to San Diego County's beaches, thanks to hordes of gelatinous intruders.

The jellyfish are back.

"They're all over the place," Encinitas lifeguard Captain Larry Giles said Monday. "It's sick. We're getting so many jelly fish stings we can hardly keep up."

Vincent Levesque, a scientist who actually breeds jellyfish at the Scripps Institution of Oceanography's Birch Aquarium, said San Diego County's beaches are visited annually by one type of jelly fish —— the "purple striped" jellyfish —— that drift in with tides.

But he said this year the purple striped jellyfish have been joined by two other types: the "fried egg jellyfish" and an extremely rare black jellyfish ——- a deeply purple plankton that can be as wide as three feet across and have tentacles stretching up to four feet in length.

The result for swimmers and lifeguards has been a pain.

Lifeguards have stocked stations with bottles of vinegar and water —— a combination that reportedly eases the pain of jellyfish stings. Shovel-wielding beach workers have been burying jellyfish that have floated up on beaches. And swimmers have been reporting jellyfish stings "every 10 minutes."

Levesque said that except for Australia's Box jellyfish and the Portuguese Man of War, which is rarely seen in San Diego's waters, jellyfish aren't life-threatening to humans.

But they do pack quite a sting through "harpoon-like" attachments to their tentacles that inject venom into fish —— and people —— who swim into them.

"It will be painful if you run into them," Levesque said.

Compared to a bee's sting, Levesque and others said a jellyfish sting spreads out farther along the skin, and the pain lasts longer, from 15 to 20 minutes.

Enrique Monpoya, a lifeguard in Del Mar, said weary lifeguards who were already stocking vinegar and water solutions in their stations simply started handing bottles out to families as they showed up at the beach over the weekend.

At the beach in Carlsbad on Monday, most people said the jellyfish invasion, which has been playing out all along the Southern California coast, was more of a nuisance than a danger.

But others said they'd had enough.

Shannon Burnell, 26, of Escondido, ran out of the water in Carlsbad after stepping on a jellyfish —— and said she wouldn't be dashing into the ocean for a while.

"They're all over," she said. "And they're huge."

Surfer Tim Mosteller, 34, of San Marcos, said the jellyfish made him hesitant about going into the water.

Lifeguard Matt Lance, meanwhile, said, "Some of the little kids are afraid to go in the water after they get stung."

Levesque said swimmers would have a hard time avoiding many of the jellyfish floating in the waters.

That's because the concurrent appearance of red tide —— an annual algae bloom that has hit local waters —— has made the sea murkier and the jellyfish harder to see.

While the jellyfish have proved a bother to most, Levesque said he's been eagerly hitting the beaches in the hope of trapping new specimens for the Birch Aquarium.

He said this year's appearance of the black jellyfish marks just the fifth time they've washed up in local waters since 1925.

Meanwhile, Levesque said, there was good and bad news for local swimmers hoping that the jellyfish would drift up somewhere else.

The good news, he said, was that there's evidence that the biggest jellyfish drifts appear to be moving further north up the coast.

The bad news, he said, is that even though the monstrous black jellyfish have only been spotted in county waters five times since 1925 —— the intervals between their appearances are getting shorter, with the last appearance in 1985.

One day they could be a yearly visitor, he said.

Contact staff writer Gig Conaughton at (760) 739-6696 or gconaughton@nctimes.com.