One of the most mysterious creatures from the deep sea washed up on a beach in Golden Bay's Farewell Spit in New Zealand.

Farewell Spit Tours guide Anton Donaldson was taking tourists on a trip Friday when he received a message that a deep-sea creature had washed up on shore.

"My colleague Andy was ahead of me and txt to say you're in for a surprise. He didn't elaborate on what it was," Donaldson told the Herald.

The group walked a little further along the beach and found a giant white lump on the shore. The tourists were shocked to come up close with a rare creature.

Donaldson told his tour group they were going to get the chance to see a giant squid, something that was a once-in-a-lifetime experience.

"I announced it to the passengers and we all got out to take a look. They were full of excitement. For most people it's a once-in-a-lifetime opportunity, or not even a once-in-a-lifetime.

"It's not a common find on any beach so if you're able to be there at the right time, because things that wash up on the beach, organic material doesn't last on the beach."

Donaldson and a passenger measured the giant squid, which had an estimated mantle and head close to 13 feet in length, not including the tentacles.

The tour guide said it looked like some of the tentacles had been chewed off, following which the creature had washed up dead.

"The tentacles on it were chewed back. It looked like they had been chewed back by some other sea creatures such as small sharks or fish. While I don't know for sure, I imagine it had been floating out there for a period of time and had washed up."

Donaldson said it was an extremely rare part of nature.

"When it's something a bit different it's a special thing to experience. But at the same time there was some sadness about a creature like that. A magnificent example of a large sea creature that lives at the bottom of the ocean unfortunately on the beach not alive anymore."

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Donaldson said the Department of Conservation has been contacted, as the giant squid has previously been sought-after by scientists.

The company's last sighting of a giant squid was in 2019 when they spotted an 18-foot-long invertebrate stranded on the sand. The majority of the giant squid spotted by Farewell Spit Tours have been around the same length.

According to AUT Lab for Cephalopod Ecology and Systematics, a giant squid can grow up to 42 feet long and weigh up to 600 pounds. These creatures usually live in a depth of about 1,640 and don't come to the surface once they are fully grown.

People relax on Durdle Door Beach during warm weather, in Dorset, Britain, July 16, 2022.
People relax on Durdle Door Beach during warm weather, in Dorset, Britain, July 16, 2022. Reuters / HENRY NICHOLLS