The carcass of a bizarre-looking creature that once spawned tales of sea monsters has been found by a snorkeler in a bay at Santa Catalina Island off Southern California. (Oarfish photo are courtesy of CIMI)

The 18-foot-long oarfish was discovered Sunday afternoon by Jasmine Santana, a marine science instructor at the Catalina Island Marine Institute. The oarfish was dead but its slender, snake-like body was intact.

The find was described by CIMI as a “discovery of a lifetime.”

ABC 7 stated Monday on its Facebook page that the carcass required 15 people to carry it up the beach.

The discovery was made in Toyon Bay, not far from Avalon, where CIMI runs a camp for kids. Instructors were unloading gear after a tall ship voyage to nearby Santa Barbara Island when they spotted Santana hauling the oarfish ashore, according to KTLA.

“The craziest thing we saw during our two-day journey at sea happened when we got home; these islands never cease to amaze,” Connor Gallagher said in a news release.

Oarfish, which can reach lengths of 50-plus feet, inhabit depths of 1,500 to 3,000 feet. They feed largely on krill and other tiny organisms and possess large, saucer-shaped eyes.

They’re believed responsible, in the times of ancient mariners, for spawning tales of sea serpents and dragons that would rise like demons to steal crewmen and sink tall ships.

They’re rarely encountered but sometimes when they die or are near-death, they surface and wash ashore.

Only a handful of live specimens have been found. Interestingly, Catalina was the site of at least one such discovery.

In 2006, a 15-foot oarfish was spotted in the island’s Big Fisherman’s Cove. Harbormaster Doug Oudin snorkeled alongside the docile creature before it eventually perished. It was collected for study.

Last year at the Baja California resort city of Cabo San Lucas, a 15-foot barely-live oarfish washed ashore on a popular beach. It also died soon after its discovery.

The modern discovery of oarfish may date to 1808, when a 56-foot serpent-like creature washed ashore in Scotland.

In 1901, a 22-foot oarfish drifted onto the sand in Newport Beach, California, becoming, according to one reference book, “the basis for many sea-serpent stories told by local bar patrons for more than a decade after its discovery.”