A giant monitor lizard joined tourists on the beach before it calmly floated just metres away from a couple in the water.
The 1.5-metre-long reptile stunned beachgoers when it emerged from woodland and walked onto the sand on the island of Ko Hong in Krabi, southern Thailand, on April 13.
Footage shows how the Godzilla-like creature ignored the visitors and calmly entered the clear blue sea. It then glided past swimmers who looked on in amazement.
With its head beneath the water, the reptile seems just like any other tourist enjoying snorkelling in the turquoise waters.
Tourist Nam Sudarat, who recorded a video while on a day trip to the idyllic island, said the monitor lizard was relaxed.
"He just ignored all the humans on the beach and went swimming. I didn't see him come back because we left," the tourist said.
The lizard swam to a nearby rock island seen in the distance where it climbed onto the surface and basked in the hot sun, with temperatures approaching 40 degrees.
Local wildlife officer Khun Weerasak said the monitor lizard was a male who lives in the jungle on the remote island. It is believed to have swam back onto the land later that afternoon before sunset once the people on the beach had left.
"This lizard will come onto the beach to collect scraps of food left behind by tourists. He's big but he's friendly. He likes to cool down by swimming in the sea," the wildlife chief said.
Earlier this month a monitor lizard sparked panic in the city of Nakhon Pathom around 800 kilometres away when it wandered into a supermarket and climbed on the shelves.
The creature spent an hour in the store searching for food before being chased away by the emergency services.
Asian water monitor lizards have a Godzilla-like dinosaur appearance and are often mistaken for Komodo dragons.
They live in canals and ponds in large cities in Thailand where they feed on fish, snakes, frogs and scraps of food left by humans.
They are aggressive when threatened and have a mildly venomous bite which sometimes carries harmful bacteria.
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