Well, here's what we found out about them.
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Though they're more commonly known as by-the-wind sailors because of their sail-like tops, their scientific name is Velella Velella. They feed on plankton and algae and their main predator is a sunfish called Mola.
If you're just hearing about these tiny organisms, they're actually not new and there's no obvious reason as to why more of them are showing up on Southern California beaches.
"Sometimes, there's just this enormous amount, and everybody really gets to see it," said Nate Jaros, the Curator of Fish and Invertebrates at the Aquarium of the Pacific. "Other times, it'll be a little patchy, and it can it happen from here up through, you know, the entire West Coast."
So why are they blue?
"The blue part is a natural pigmentation that they have that just protects their more sensitive parts from the UV rays of the sun," Jaros said.
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Though they're not exactly jellyfish, they are related to them.
By-the-wind sailors don't sting like jellyfish but they do have tentacles on the bottom that can irritate the skin.
However, they're mostly harmless to humans. For more information, watch this video from Dana Wharf.