"I woke up and heard a strange scratching sound ... at first I thought it was thieves" she said. "I turned on the light and saw this monster working its way along the wall using his claw."
Ms Duan, from Suining in southwest China, said she then grabbed a shoe and beat the snake to death. She reportedly preserved its body in a bottle of alcohol which she gave to the Life Sciences Department at China's West Normal University in Nanchang.
Snake expert Long Shuai said the discovery of the creature, which is 40cm long and the thickness of a little finger, was "truly shocking".
"We won't know the cause until we've conducted an autopsy," she said.
Misterios gato alado:
The long-haired white feline was born a normal kitten, but started to develop furry wing-like appendages on either side of its back when it was just a year old.
Scientists believe the growths may be the result of a genetic mutation caused by chemicals during its mother's pregnancy. Alternatively, the cat which was discovered in Chongqing, China, may be a freak that developed from two embryos.
However, the puss does not seem to be bothered by its wings, and it was quick enough to swoop on any cat biscuits dished up.
Chongqing is known as one of China's hottest cities and, following the discovery of this cat, the air there is certainly getting a bit moggy.
Los enlaces en Signs of Times: The Living Planet
The identity of this creature, which reportedly washed up on a New York beach last month, has captivated the blogosphere and is dividing animal experts.
The beast, dubbed the Montauk Monster after the Long Island resort where it was discovered, has a hairless, leathery body, sharp teeth and what appears to be a beak.
A photo of the animal appeared on the gossip website Gawker earlier this week under the headline “Dead Monster Washes Ashore in Montauk”, and the story has since been picked up by US networks Fox News and CNN.
The woman who claims to have taken the original photo on Montauk beach on July 12 says she had no idea what the creature was.
"We were looking for a place to sit when we saw some people looking at something," said Jenna Hewitt.
"We were kind of amazed," the 26-year-old added, "shocked and amazed."
Other locals have now come forward to say they saw the animal, which has been variously identified by blog commenters as a dog, raccoon, and shell-less sea turtle.
The dog theory, which depends on the creature's beak actually being a nasal cavity, currently appears to have most support.
An initial theory that the image may be a hoax produced as part of a viral marketing campaign has been undermined by the number of witnesses.
It is unclear what happened to the corpse. Michael Meehan, a waiter at a beachside restaurant in Montauk who also claims to have seen the beast, said that animal control were called, but others say it was removed before they arrived.
"They say an old guy came and carted it away," Ms Hewitt told New York magazine. "He said, 'I'm going to mount it on my wall.'"