Villagers were terrified when they found a mystery creature that resembled a Xenomorph from the 'Alien' movie.

The locals were fishing in the river when they saw the strange decomposed body stuck by the roots of mangroves in a swamp in Nakhon Si Thammarat, Thailand, on January 20.

Footage shows scared fishermen watching nearby as authorities measured the dead creature half-buried in the quagmire.

It had an elongated head with sharp teeth in its mouth. While already dead, the rotting skin appeared glossy like that of the Alien character.

Crab hunter Pinij Bansuwan said: 'I was setting my traps when I saw the large creature with sharp teeth. It looked like an alien.

'I panicked and ran. I have never seen anything like that before in our river. I was born and grew up here.'

He told his neighbours about the shocking discovery and authorities who contacted veterinarians.

Experts from the Department of Marine and Coastal Natural Resources and the Lower Gulf of Thailand Marine and Coastal Resources Research Centre arrived for an inspection.

They took the boat to the forest and walked through the mud for 164ft (50m) from the banks before finding the alien-like creature.

They initially identified it as a false killer whale that inhabits the deep sea but took samples to confirm.

The samples were taken for laboratory analysis, including stomach tissues and head.

One of the researchers, Rattanaporn Phakphian, said: 'It looked like a juvenile. We are unable to determine the gender due to decomposition.'

The expert added the 12ft (4 m) baby whale was likely stranded due to winds and high tides.

Rattanaporn said: 'It could have been there since December and was trapped in the mangrove forest.'

The false killer whale is listed as Near Threatened on the IUCN Red List and is also included in CITES Appendix II due to factors such as a declining population, the threat of habitat loss, and human-induced activities, including entanglement in fishing gear and depletion of their prey.

The Xenomorph is the iconic alien creature from the 1979 'Alien' franchise directed by Ridley Scott. The creature is known for its terrifying and unique appearance and its role as the primary antagonist throughout the series.