One of my fosters has a tail very similar to that. It's ironic to me that the "breed" originated with a rescued moggy. My ring-tailed foster, Buster, has a littermate who is a bobtail, meaning that Buster has a 66% chance of also carrying the bobtail gene. But obviously the only way I know he might be a carrier of that gene is because I have his brother who happens to manifest the bobtail trait. It would be funny (from my rescue perspective which makes me very much against the deliberate creation of new "breeds") to see someone try to make a new breed from Buster and one of his relatives only to find out that 25% of the kittens were not only not ringtails, but they didn't even have tails at all!