Beachgoers were left shocked after they spotted a "monster" barrel jellyfish at Polkerris Beach in South Cornwall, United Kingdom, earlier this week.

Speaking to Cornwall Live, Wednesday, July 15, Ben said he had visited the beach with his son, Jack, and daughter when they spotted the creature.

"There were lots of families on the beach that morning. We were swimming and noticed a small regular jellyfish, to begin with, which we just avoided. I got out briefly, and my kids Jack and Evie started shouting frantically at me to come and look over the harbor wall. I literally couldn't believe the size of the monster jellyfish," Ben told the newspaper.

"Lots of people gathered round to see what the fuss was. There were lots of gasps of disbelief, and some people that were still in the water quickly made their way back on to the beach. I wonder if it's to do with the very warm weather we have had in the last few weeks, but it looked like something out of a film," he recalled.

It was not clear who identified it as a barrel jellyfish.

Barrel jellyfish, which can sting humans, are often found in the Adriatic, Mediterranean Sea, and the northeast Atlantic. They often wash up on the beaches in May or June.

"They have 8 arms, each frilly in appearance. These frills actually contain their small stinging tentacles that surround hundreds of little mouths. The sting of the barrel jellyfish is not normally harmful to humans, though if you find one on the beach it's best not to handle it as they can still sting when dead," the Wildlife Trusts, an organization in the U.K., wrote on their website.

Though jellyfish is not an unusual sight, Ben said he had only seen small ones.

"It's the first time I've seen jellyfish on the south coast this year, although we did see a small swarm off Tolcarne beach a couple of weeks ago," Ben told the newspaper.

Jack managed to capture a video of the jellyfish.

The incident comes exactly a year after a human-sized giant barrel jellyfish was spotted by divers off the coast of Cornwall. The video of the jellyfish soon went viral.

A picture shows a jellyfish in the port of Ginostra on June 16, 2016, on the island of Stromboli. GABRIEL BOUYS/AFP/Getty Images