Thousands of jelly-like sea creatures washed up on the shores of Huntington Beach in Southern California, making beach-goers curious about what exactly the odd things are.

On Facebook, Ryan Rustan wrote that he was walking on the beach on Nov. 28 when he "felt little water balloons popping under my feet, super squishy."

He said he looked down and didn't know what the odd, little gelatinous balls were. "Couldn't tell if they were jellyfish or eggs but there are thousands up and down the beach... what are they?"

Huntington Beach sea blobs People walking on the beach said they saw maybe thousands of the squishy blobs. (Photo: Don Coursey/Facebook)

Don Coursey posted several more images to the same Facebook group. Guesses ranged from jellyfish eggs to burrowing sea cucumbers to sea salp, a type of translucent sac-like sea creature.

Coursey told KTLA that he was walking on the beach when he spotted hundreds, or maybe even thousands of the unidentified creatures. He said he's been walking on that beach for decades and has never seen anything like it.

"It feels like Jell-O," Coursey said. "If you were a little kid, you'd love to have something like this so you can drop it down your sister's shirt."

Huntington Beach sea creatures in the sand The mysterious creatures make paths in the sand. (Photo: Don Coursey/Facebook)

Christopher G. Lowe, a marine biology professor at Cal State Long Beach and director of the university's shark lab, told KTLA that the school's resident invertebrate expert says they are sea cucumbers.

Matt Bracken, UC Irvine associate professor at the Department of Ecology and Evolutionary Biology, however, told the Orange County Register that they are likely "pelagic tunicates," otherwise known as salps.

"These marine invertebrates look sort of like jellyfish, but they are actually more closely related to vertebrates (e.g., humans) than to other invertebrates," he said. "They occasionally bloom off the California coast."

blobs spotted on Huntington Beach Some people guessed these were burrowing sea cucumbers. (Photo: Don Coursey/Facebook)

"I've never seen anything like that before, it looks odd," Huntington Marine Safety Lt. Claude Panis, who has worked for the lifeguard department for 38 years, told the Orange County Register.

Panis said that the mysterious arrival of the creatures might be due to a lingering effect of the dwindling El Niño. And that, he said, also may explain why there have been so many stingrays close to shore this year.

"There's all kinds of weird things happening," he said. "It's just strange."

While the experts have their guesses, beach-goers have more interesting hypotheses:

"Baby tremor monsters."

"Coyote eggs."

"Ewww. Creepy sea creatures."

"Aliens sent here to sick our brains out and rule our world. Just sayin."

Mary Jo DiLonardo Mary Jo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.