A marine science instructor snorkeling off the Southern California coast spotted something out of a fantasy novel: the silvery carcass of an 18-foot-long, serpent-like oarfish.

Jasmine Santana of the Catalina Island Marine Institute needed more than 15 helpers to drag the giant sea creature with eyes the size of half dollars to shore on Sunday.

Staffers at the institute are calling it the discovery of a lifetime.

Incredible: An 18-foot-long oarfish found dead in the water off Catalina Island near Los Angeles, California

‘We’ve never seen a fish this big,’ said Mark Waddington, senior captain of the Tole Mour, CIMI’s sail training ship. ‘The last oarfish we saw was three feet long.’

Because oarfish dive more than 3,000 feet deep, sightings of the creatures are rare and they are largely unstudied, according to CIMI.

The obscure fish apparently died of natural causes. Tissue samples and video footage were sent to be studied by biologists at the University of California, Santa Barbara.

Science instructor Santana spotted something shimmering about 30 feet deep while snorkeling during a staff trip in Toyon Bay at Santa Catalina Island, about two dozen miles from the mainland.

An illustration of Bank’s Oarfish, circa 1850, the giant fish that inspired tales of sea serpents. The 18-foot oarfish found off California took 16 people to haul ashore

‘She was snorkeling and sees this giant fish at the bottom of the ocean,’ Waddington told KTLA. ‘She swims down and grabs it by the tail and swims it to the beach. It was awesome. There were people sprinting to go and see this fish.’

Waddington said Santana dragged the fish ashore because ‘she said, “nobody will believe me”.’

After she pulled the carcass by the tail for more than 75 feet, staffers waded in and helped her bring it to shore.

The carcass was on display Tuesday for 5th, 6th, and 7th grade students studying at CIMI.

The oarfish, which can grow to more than 50 feet, is a deep-water pelagic fish — the longest bony fish in the world, according to CIMI. They are likely responsible for the supposed sea serpent legends throughout history.

The giant oarfish was first discovered in 1772 by Norwegian biologist Peter Ascanius. It’s formal scientific title is Regalecus glesne, but the fish is also known as king of the herring, Pacific oarfish, streamer fish and ribbon-fish.

The longest recorded specimen clocked in at 26 feet, however, the species is believed to grow as long as 50 feet and weigh as much as 600 pounds.

Like the equally mysterious giant squid, the oarfish would go on to enchant fisherman and sailors and inspire stories of sea monsters.

The fish lives at extreme ocean depths, between 656 feet (0.2 kilometers) and 3,280 feet (1 kilometer) deep.

In 1996, a group of Navy Seals found a 23-foot long oarfish off Coronado, near San Diego, California.

In 1996, Navy Seals pulled ashore this 23-foot oarfish that was found off the coast near San Diego, California

The Catalina fish is currently on ice while the fate of the carcass is decided.

‘I am pushing to bury it and wait for it to be naturally cleaned so that we can then take the skeleton and articulate it and have it on display,’ said Waddington. ‘That is what I hope will happen.