Sea Monster From The Depths Of The Ocean Washes Up On California Coast (VIDEO)

The monstrous carcass of a legendary, eel-like creature, thought to have inspired tales of giant sea serpents, has mysteriously washed ashore in California.

A marine science instructor spotted something fishy when she was snorkelling off the Southern California coast.

The oarfish is the longest bony fish alive and can grow up to a mammoth 17 metres in length

Jasmine Santana Catalina Island Marine Institute (CIMI) was chilled to her core when she saw a massive eye staring at her from the sandy bottom, the institute said in a statement.

"Her first reaction was to approach with caution, until she realised that it was dead," it read.

The experienced diver needed more than 15 helpers to drag the giant sea creature to shore.

"She was snorkeling and sees this giant fish at the bottom of the ocean, Mark Waddington, senior captain of the Tole Mour, CIMI's sail training ship, 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."

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

Waddington said Santana dragged the fish ashore because, she said, "nobody will believe me".

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