He said: ‘I found it washed up, put it back into the sea but it was clear it was holding itself out of the water to breath air, so I allowed it to wash up again and it was just moving around, breathing I imagine.’

Residents on the island said there had been large numbers of the marine ‘mutants’ washing up recently but so far nobody has been able to identify them.

Some have suggested the creature in the video is a sea leech, a sea lug, a bed bug – or even a ‘mutant alien life form’ emerging from the deep.

Chakchai Inyapong, who works at a scuba diving business on the island, said: ‘I did not see these on the beach before, until a few weeks ago. They look harmless.

‘They are cute. A lot of people joked that they’re aliens, but I’m not sure about that.’

Liam added: ‘It was definitely very odd. It was about five inches long and two or three inches wide.

‘People thought it was a sea cucumber but they can move themselves along the floor and this was unable to move itself.

‘It seemed to have something inside which was moving around. The skin was almost transparent and you could see something else inside.’