The hideous, mildly terrifying and rarely sighted frilled shark has turned up in waters off southeastern Australia.

The species is considered a "living fossil," as its ancestry dates back 80 million years, 

The shark was caught by a fishing trawler in waters near Lakes Entrance in the Gippsland region of the state of Victoria.

Simon Boag, from the South East Trawl Fishing Association, said it was the first time in living memory that a frilled shark had been sighted.

"We couldn't find a fisherman who had ever seen one before," he said.

Frilled shark

Simon Boag, from the South East Trawl Fishing Association, said it was the first time in living memory that a frilled shark had been sighted. (South East Trawl Fishing Association)

"It does look 80 million years old. It looks prehistoric, it looks like it's from another time!"

He said local fishermen were left scratching their heads at the sight of the two-metre-long creature, whose head and body resemble an eel, but whose tail is more reminiscent of a shark.

Australia's national science agency, the Commonwealth Scientific and Industrial Research Organisation (CSIRO), confirmed the fish to be a frilled shark. While the species is known to the scientific community, it was a nonetheless rare and bizarre find for local fishermen.

"It has 300 teeth over 25 rows, so once you're in that mouth, you're not coming out," Boag said.

"Good for dentists, but it is a freaky thing. I don't think you would want to show it to little children before they went to bed."

The species has been found as deep as 1,500 metres, but generally it lives in waters shallower than 1,200 metres.

Boag said this frilled shark was caught at 700 metres, but there should not be any concern about repeat catches.

"Almost all the grounds deeper than 700 metres are closed to trawling, so there wouldn't be any pressure on them and there'd be very few caught," he said.

"This guy was just unlucky."

After being declined by the CSIRO, the frilled shark is believed to have now been sold.