I have a 4 year old cat that is very tame, sweet and affectionate. She accepts getting petted at all times and she enjoys it, sometimes she even shows me her belly for belly rubs. But on rare occasions, she asks me to get petted (as always) and then when I’m petting her as usual, she suddenly turns and bites me HARD (it bleeds), sometimes hisses. If I don’t quickly withdrawal, she will scratch me too. Her body language doesn’t say she’s play-fighting, she’s really fighting me. Airplane ears, enlarged pupils, arched back and she looks paralyzed/frozen with a psycho look lol. After a few minutes she forgets about it and gets sweet and tame again, accepting being petted. That aggressive behavior is unpredictable. Why does that happen? Am I doing something wrong?