IS there a Beast of Birchencliffe?
That was the question posed after a motorist called in at a Huddersfield petrol station.
The late-night shopper leaving Birchencliffe Service Station in Halifax Road saw a huge black cat slink off into countryside along Burn Road.
Police are treating the sighting seriously and warning people to keep away from the animal.
Sgt Tim O'Sullivan, of Huddersfield police, said the feline was seen at 1.30am by the shocked young man.
The beast was described as `enormous' with gleaming yellow eyes.
Officers immediately checked with a Rastrick pet owner who keeps exotic animals but none were reported missing.
"We are concerned it may have escaped from somewhere," said Sgt O'Sullivan.
He appealed to the public to report any further sightings.
"It must have been massive," he added. "If you do see it, notify us and don't go near it."
Nocturnal black leopards and panthers have been spotted in England for decades.
Most big cat sightings in Britain are thought to be black leopards or pumas.
One of the most persistent sightings is the Beast of Bodmin in Cornwall.
Black leopard pairs with cubs have been reported in Worcestershire and Herefordshire and puma pairs in central Wales.
Most of the cats were kept as exotic pets and released into the wild when new laws in 1976 made it illegal to keep them without a licence.
Jaguars, jungle cats, golden cats and leopard cats have all been spotted in the UK.
There have also been reports of timber wolves, coyotes, wolverines, racoons, lemurs and even apes and monkeys.