A skeletal impossibility. Mange doesn't grotesquely distort other physical chatacteristics of an animal, it just makes hair fall out. While this will cause quite a different look for any furred creature, it won't make a tail that was half as long as the animal become twice as long as the animal.
Reason trumps emotion in science... or should.
Don't know what pics you are looking at, but the pic at post #1 on this thead is a canine. Maybe a coydog or not. Reason trumps.
Chubacabra is for weak minds.
And there are diseases that distort the skeletons of animals.
Rickets, for instance, in humans. Observable in bone structure, long after the meat is gone.
/johnny