A creature which looks like it's crawled out of the devil's belly turned up on the end of a Coromandel teen's line during a Halloween fishing trip in the region.

Port Charles teen Marco Salewsky, 14, thought he'd escaped Halloween revelry on Saturday when he chose to go fishing off his local wharf instead of heading along to a party with his family.

The 1.8 metre-long snake eel that Marco Salewsky, 14, pulled in while fishing at Port Charles on Halloween. Photos: Marco Salewsky/Supplied.

"I said just drop me off at the wharf, then I got that thing," he says.

The creature is known as a snake eel, or serpent eel, says Niwa fisheries scientist Peter McMillan.

"This one is 1.8 metres but they can grow to at least two metres.”

Marco was fishing with a rod and line, using a live bait when he said the creature turned up on the end of his line and gave him "quite a fright".

"When it was coming up I thought it was a [regular] eel, then I saw its teeth come out," he says.

He thinks it spotted his bait and pounced out of its usual hiding burrow in the sand.

Marco says he goes fishing often and neither he nor other fishermen he'd talked to in the area had seen anything like it before.

"It's definitely the oddest thing I've seen come out of the ocean."

He got it on to the wharf, where it entangled itself with the line and died, he says.

"I guess it was freaking out."

He's not sure what will become of the snake eel, but wants to take it along to show his class at Coromandel Area School.

For now, it's at home drying in the sun, where it continues to twitch.

"It's stiff, but if you pull it's skin the nerves still twitch."

Snake eels are found in warmer water in the north-eastern Atlantic, northern New Zealand, Japan and the Mediterranean, says Peter.

'They are rarely seen by humans because they burrow into the sand with just their heads poking out until they pounce on passing fish to eat.

"It can probably see you before you see it."

The snake eel, or serpent eel, was attracted to Marco's live bait, pictured here in its mouth.