The crew of sailing school vessel Tole Mour and Catalina Island Marine Institute instructors hold an 18-foot-long oarfish that was found in the waters of Toyon Bay on Santa Catalina Island, Calif. More than 15 people were needed to help marine science instructor Jasmine Santana drag in the dead serpent-like creature.

LOS ANGELES — 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.

“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 3 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.

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.

“She said, 'I have to drag this thing out of here or nobody will believe me,”' Waddington said.

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