A farmer in China has got the fright of his life after finding a spider with a lump that looks like a stamp on its abdomen.

The 'unbelievable' arachnid is a Chinese hourglass spider and extremely rare, according to an expert.

These spiders, a type of trapdoor spider, use their protruding bellies to protect themselves against their enemies and all of them bear 'mysterious' markings, the expert adds.

Different from other spiders, Chinese hourglass spiders don't spin webs. Instead, they live in underground nests which they make using their silk threads and mud, scientist Zhao Li explains.

They feed on bugs that pass their burrows. Whenever there is danger, they would protect themselves by blocking the entrance of their nest using their 'stamp'.

Formally known as Cyclocosmia ricketti, it is one of the earliest spiders to have been documented in China and has been sighted for just eight times in the country since 2000, Zhao says.