A bizarre sea creature has baffled internet users after it washed up on a Californian beach.

The slimy monster appeared to have no discernible features, such as eyes or a mouth.

It also sports two huge lumps sticking out of one end of its body, the Daily Mail reported.

The beach walker who found the bizarre-looking monster at Leo Carrillo Beach, Malibu, shared pictures online to see if anyone could work out its identity.

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Reddit user xxviiparadise said: "It weighed around seven pounds [3.2kg] and if I had to guess about five inches [13 cm] wide."

One commenter speculated that it could be some kind of sea snail.

Another wrote: "Looks like whatever lives inside the seashell."

Reddit user PacificKestrel claimed to have solved the mystery.

After asking if it was found in southern California, they said: "I'd say that, my friend, is a long-dead sea hare."

The California sea hare is a common species of sea slug found off the west coast of the US and northern Mexico.

The animals grow up to 75cm long and can weigh as much as 7kg.

The slugs eat red algae from the sea floor, which gives them a reddish colour, and also grants them toxic properties, meaning they have few natural predators.

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This is not the first bizarre sea creature to have sent the internet into a frenzy this year.

In May, a mysterious rotting carcass washed up on an Indonesian beach, leaving online commenters baffled as to what it might be.

Fisherman Asrul Tuanakota, who discovered the 50ft (15m) creature on the northern shore of Seram Island, had guessed it could be a giant squid because it appeared to be covered in tentacles.

But Alexander Werth, a whale biologist at Hampden-Sydney College in Virginia, and George Leonard, chief scientist at the Ocean Conservancy, eventually solved the mystery.

The pair said that the carcass was almost certainly a baleen whale, as bones protruding from the mass of rotting flesh appeared to be feeding plates from the animal's mouth, used to filter food.

One user suggested that the creature was a 'long-dead' California sea hare, a common species of sea slug found off the west coast of the US and northern Mexico. Photo / Genny Anderson / Wikimedia
One user suggested that the creature was a 'long-dead' California sea hare, a common species of sea slug found off the west coast of the US and northern Mexico. Photo / Genny Anderson / Wikimedia

Seram Island is also close to a migration route used by baleen whales, UPI reported.

The "tentacles" were probably made from fatty blubber that had been torn into strips by scavenging predators.

Whale carcasses typically sink into the depths of the ocean after death, though under the right circumstances the body can fill with gases as it decomposes, allowing it to float.

In such cases the body can then drift ashore.