Mysterious rare purple shell washes up on shores of beach after long absence

A student was enjoying a sunset stroll on a beach in La Jolla, California, when she came across something very rare.

Anya Stajner, a Ph.D. student at UC San Diego's Scripps Institution of Oceanography, spotted a tiny, bright purple shell - and recognized its significance. 

The spokesperson added, "Janthina are typically found in subtropical to tropical seas, and their stranding along the Southern California coast is often linked to warmer offshore waters flowing toward the shore."

Janthina protect themselves with a "camouflage strategy" known as countershading.

They point their front side to the sky while floating, appearing in a darker color to blend in, according to the Texas Saltwater Fishing Magazine (TSFM).

The snails can reach about 1.5 inches in height and, while safe to pick up, they can secrete a purple ink that can leave a stain.

"I've heard of them … I've seen them either on the news or social media. It is cool, but it also makes me wonder why they're showing up," Whitney told FOX 5.

"Which is when we had both an El Niño event and a warm blob of water that sort of combined, and it was this massive marine heat wave," said Stajner.