It has to be one of the most terrifying fabled creatures in British history.
The dreaded Shug Monkey, about eight feet tall, is a huge hybrid monster said to haunt the rural lanes of Cambridgeshire.
It allegedly has the body of a jet-black dog and the face of a primate, with blazing red eyes and long flattened 'claws' like human fingernails.
Sometimes the demonic animal is reported to walk upright on its hind legs, while other times it's seen running on all fours.
And some locals believe catching a glimpse of the dark figure is an omen of death.
Now, experts finally reveal the truth behind the legendary beast, which sits alongside Loch Ness and Black Shuck in Great British folklore.
Robin Dunbar, evolutionary psychologist at the University of Oxford, said such apparitions 'are by no means uncommon'.
'Strange visions are common on dark nights, perhaps a little worse for wear from a pleasant evening in the pub,' he told the Daily Mail.
Said to haunt Cambridgeshire, the Shug Monkey has blazing red eyes and long flattened 'claws' that are shaped like human fingernails
Shug Monkey reportedly haunts Slough Hill Lane which leads from the village of West Wratting to nearby Balsham in Cambridgeshire
The Shug Monkey is supposed to haunt Slough Hill Lane, which leads from the village of West Wratting to nearby Balsham, just southeast of Cambridge.
Reported sightings in the area go back more than a century, according to folklore expert Daniel Codd, who studies history and the paranormal in Britain.
In his 2010 book 'Mysterious Cambridgeshire', he describes the Shug Monkey as 'a 'large, rough-coated animal with big, blazing bright eyes'.
He writes: 'Children would avoid the place after dark in the early 1900s, but quite what this shaggy-haired monstrosity's exact status was is unclear.
'It does not appear to have been thought of as an animal such as a Yeti-type creature, or even an escaped primate.'
Dr David Waldron, a historian and anthropologist at Federation University in Australia, said 'shug' comes from the Old English 'scucca' meaning devil.
And folklore surrounding the beast is often linked with the shape-changing devil dog legends of that region, like the Black Shuck.
'Shug Monkey is quite often tied into lonely lanes, thresholds, and for travellers, operating as a warning figure or omen bringing tales of misfortune,' he told the Daily Mail.
Most visions of the half monkey, half dog are likely triggered by the odd shapes along the road, coupled with poor lighting conditions at night.
Sometimes the demonic animal is reported to walk upright on its hind legs, while other times it's seen running on all fours.
The legend of the Shug Monkey
The Shug Monkey is a Cambridgeshire folklore legend dating back at least 100 years.
It is believed to have the body of a black dog and the face of a monkey with demonic eyes, usually described as red in colour.
In 1954, local writer and broadcaster James Wentworth Day first related stories of the Shug Monkey in 'Here Are Ghosts and Witches'.
A local Police Constable A. Taylor, who had heard the stories of the creature in his youth, described it to Wentworth Day as 'a cross between a big rough-coated dog and a monkey with big shining eyes'.
However, most visions of the half monkey, half dog are likely triggered by the odd shapes along the road, coupled with poor lighting conditions at night.
'Hedgerows, gates, and moving shadows "jump" into animal forms,' Dr Waldron said.
Alternatively, people could be seeing a dog, a fox, or a deer, while mist and car headlights create 'halos and glare that enlarge heads and eyes'.
As for the demonic red eyes, larger animals in Britain have a reflective layer behind their retinas that may make their eyes glow red.
According to Dr Waldron, there is 'no definitive evidence' that the Shug Monkey exists in physical form, although it certainly exists 'as a living tradition'.
'England is also a difficult environment for a large animal like that to exist undetected,' he said. 'The name is what turns fear on a lane into a story others can share (and, sometimes, relive) and it connects people to heritage, the landscape and tradition.'
Tim Coulson, a professor of zoology at Oxford University, said he grew up a few miles from the area where the Shug Monkey is supposedly sighted.
'I sadly never encountered the Shug Monkey, but this is no great surprise as I am confident it does not exist,' Professor Coulson told the Daily Mail.
'Once a story like this starts, people often claim to have seen it.
'They have likely caught a fleeting glimpse of a fox or badger or deer and then convince themselves they saw the mythical Shug Monkey.'
Dr Brian Sharpless, clinical psychologist and author of 'Monsters on the Couch', called descriptions of the Shug Monkey 'fascinating'.
But alleged witnesses of the beast may be experiencing 'pareidolia' - the tendency of the human mind to see things from everyday visual stimuli.
'Our brains tend to construct meaning out of chaos,' Dr Sharpless told the Daily Mail.
'Pareidolia is more likely to occur in low light conditions and in stressful, scary environments.
'Therefore, our brains might be creating hairy monsters out of far more mundane objects like trees, shadows, or red deer.'
Dr Jason Gilchrist, an ecologist and lecturer at Edinburgh Napier University, thinks the mystery of 'cryptids' - animals whose existence is disputed - is 'self-perpetuating'.
Some of the most famous cryptids worldwide are Loch Ness, Bigfoot and the Abominable Snowman.
'Reports over time are likely to be the result of 'expectant attention' - people seeing what they expect to see,' Dr Gilchrist told the Daily Mail.'
'Once a myth or story of something exotic takes hold, people want to see 'the monster' and are predisposed to see or interpret things that their mind then fits to the search image for "the monster".
'If it is any creature known to science, there would have to be a breeding population of them for individuals to be spotted over a hundred year period.'