The carcass of an 18-foot oarfish was found off Catalina Island on Sunday.

Jasmine Santana, a marine science instructor, spotted the giant fish while snorkeling off the Southern California coast. She needed 15 people to help bring it to land, the Associated Press reports.

"I recognized it once I saw it and I was like, 'Oh my god, this is an oarfish, but it's huge!' And there's no way anyone's going to believe me if I just tell them, so I decided I should grab it and pull it out of the water," Santana told KPCC who dragged the carcass for more than 75 feet until Catalina Island Marine Institute staffers helped her bring the oarfish to shore.

Local marine biologists were shocked by the serpent-like creature. "It just amazed me," Jeff Chace, director of the Catalina Island Marine Institute, told the Los Angeles Times. "This is a once-in-a-lifetime discovery."

Oarfish can grow to more than 50 feet and are able to dive more than 3,000 feet deep, where they are rarely seen dead or alive, according to the Catalina Island Marine Institute.

The 18-foot long oarfish found in Toyon Bay off Catalina Island most likely died of natural causes. Tissue samples have been sent to researchers at University of California Santa Barbara and elsewhere to see how the creature died and made its way to Southern California.

The fish, which was on display Tuesday, is too large to be stored and will probably be buried in three feet of sand and left to decompose.

This isn't the first time an oarfish made its way to dry land this year.

In August, a 13-foot carcass of a mysterious sea creature washed ashore in Spain. Called a “horned sea monster” and “mutant fish” -- the giant creature was found by a beachgoer who noticed the animal’s head.

Gary Griggs, the director of the University of California Santa Cruz's Institute of Marine Sciences, believed the sea creature was an oarfish. "Based on my vast experience as an ichthyologist, this looks like a ribbon fish or oarfish," he told The Huffington Post.

In June, rare footage of an oarfish caught swimming of the Gulf of Mexico was captured. It's considered the “first ever” high quality footage of the sea serpent ever recorded.

“We weren’t looking for oarfish,” Mark Benfield, a professor at Louisiana State University who was present when the footage was taken, told National Geographic. “This was just sheer luck. We happened to be in the right place at the right time and we were able to spend some time with this oarfish.”