If it's not Manx, it's just a cat.
This is a nice site with lots of details about Manx cats with some stunning photos although I didn’t see the tale explaining why he has no tail. Apparently, Manx cats are grumpy and reluctant to do what they are told. When Noah was loading the animals on the Ark, Manxie was too busy chasing mice to come on board. well, the rains started, and Noah and the lads were pulling up the aft hatch when right at the last minute, as the hatch slammed shut, Manxie dove through the gap cutting off his tail. And God left him that way ever since as a caution to other animals to do what they are told.