A waterspout tornado formed under a thick cluster of storm clouds in Thailand.

Footage shows the funnel-shaped weather phenomenon under the cloud mass off the coast of Koh Lan island in Pattaya on September 2.

Fisherman Rung Namkem spotted the waterspout while resting on his boat after a day of trawling.

He said: 'It looked terrifying. Seeing it made me think twice about taking the boat back to the mainland.'

Waterspout tornadoes form when wind merges from opposite directions near the water's surface, creating a small area of spin. Warm air at the surface causes the spinning air to rotate faster and start to rise – picking up water simultaneously and forming the distinctive elephant-funnel shape.

As warm air rises, the cooler air moves in below and rises. Sometimes the air spins so fast that it stretches, and a funnel appears from the water to the thunderstorm cloud above.

Waterspouts are generally not dangerous but can risk aircraft flying through the area and coral reefs and marine life in the water immediately below. Sailors should also try to avoid waterspouts as the power of the wind can cause damage.

They very rarely damage buildings as they dissipate when they reach land. However, they are dangerous for boats caught in their path or aircraft that fly through them.