A shocked resident discovered "alien worms" forming a circle in his back garden in Chumphon, southern Thailand on March 14.

The tiny worms are called fungus gnat larvae. The circle is formed when the leading larvae mistakenly hooks up with the larvae at the tail of their line forming an endless loop.

A shocked resident discovered ‘alien worms’ forming a circle in his back garden.

Bizarre footage shows the mass of grey worms circling on the ground in Chumphon, southern Thailand, on March 14.

Confused resident Jeab Narongdech said: ‘I was very excited when I saw the group of tiny worms moving in a circle in my back yard. I’ve never seen anything like it before.’

The tiny worms are called fungus gnat larvae. The circle is formed when the leading larvae mistakenly hooks up with the larvae at the tail of their line forming an endless loop.