No cat can ever get this way by accident. This person might have even helped create this abomination. He/she needs to euthanize it - or learn to live with it.
Oh yes they can; if you have enough cats over your lifetime you will find a few attack kittys amongst the bunch. True attack kitties are born, and need no help to be rotten through and through. I have had two, and my mother had a really bad one that she called Bad Bob. Bad Bob was really bad and though my mother loved and spoiled him (and attempted discipline) and from birth he was an indoor kitty, as he got older he became feral by his own choice.
I had one that was so territorial that he would stand at the top of the stairs and growl down anyone that tried to go up the stairs.
He hooked me one time all the way through my skin like a fish hook (in one side and out the other) because I picked him up. I played hell trying to get him to retract his hook from out of my arm. He was finally made to live out his “bitter” life outdoors. He was a happy fellow after that... killing rabbits, snakes, and whatever on our country property. The cat even had an evil look to him. He was a orange tabby with the most vivid true green eyes I have ever seen on a cat. He was a total terror from the time we brought him home at 8 weeks old. We thought he would chill out, but he never did. He finally died of old age years ago.
Ever had a calico?