Beautiful cat! Tail biting and growling/aggression towards the tail could be due to impacted anal glands or fleas in tail area. I've read that it can sometimes be due to pain in the spine or pelvis. Or could be kitty version of OCD due to anxiety, stress or boredom. Our cat was doing this years ago and for her, it turned out to be impacted anal glands that the vet (and 2 techs!) emptied. She was not amused! Caramella could also just be having fun too and being silly but just wanted to throw those other ideas out there just in case.