(CNN) — A large concentration of bioluminescent plankton has formed in the water near San Diego, treating late-night beachgoers to its eerie, electric blue glow.
It was first spotted on Monday and scientists don't know how long it will last.
Daniel Humphrey stayed out late on Monday night to take these photos of the bioluminescent waves at Torrey Pines State Beach near San Diego.
He said he heard about it on the news and went to see it for himself.
"I'm paying for it today, but it was so worth it," Humphrey wrote on Instagram. "Seeing that electric blue flowing through the waves was an incredible experience, and the pictures certainly don't do it any justice."
Photographer Ev Yorobe also heard a rumor that it could be going on, so he went to check it out.
The phenomenon is caused when huge numbers of dinoflagellates form in what's known as a bloom, according to the Scripps Institution of Oceanography at the University of California, San Diego.
It's actually called a red tide because the reflection of light off the tiny creatures' bodies gives the water a red tint.
This bloom was spotted from La Jolla up to Encinitas, which are about 20 miles apart.
Jamie Feldman rushed out to see it on Monday night, and hopes to go scuba diving with the plankton.
"As the waves crash you just see this flash of electric blue," she said. "It's mesmerizing."
Jamie Feldman says the bioluminescent glow from the red tide near San Diego is mezmerizing.
Scripps Oceanography said red tides are very unpredictable, so there's no way to tell how long it will last.
The last red tide in the area was in 2013 and lasted a week. A bloom in 2011 stuck around for a month.
The bioluminescent display is best seen on a dark beach, at least two hours after sunset.
If you see the bioluminescent red tide, please share your photos and videos with CNN by tagging them with #CNNweather on Twitter, Instagram or Facebook.