I have two cats eldest is 3 and the other is 2. Had both cats since kittens and never had any problems.
The eldest cat was bought from a lady who's cat got accidentally caught before she was spayed. She's always been one for being on her own and never a knee cat, however would come for a stroke and tolerate normal family life.
Just lately eldest cat has been snappy. She bit Ds who's 13 when he tried to move her off his homework (picked up nicely talking to her calmly) When Dd2 goes to stroke her she's bitten her twice and this morning scratched the side of her face. Dd was in no way threatening and she saw her before stroking her so didn't catch her by surprise. The only person the vat normally 'warms to' is Dd1 she's send her favourite and normally loves to sleep on her bed. Last night Dd got into bed and the cat howled at her and tried to scratch her!! Just for getting into bed!!
This isn't all, she's starting to constantly bully the other cat, really going for her, eating her food and spitting. She waits for her behind the sofa and pounces on her. They have been together since we rescued younger by two years ago and always got along fine. Younger cat is much more timid and jumpy so is terrified!
What is going on with her? She's been worse over the last 2 months but yesterday and today has for so bad I can't cope. We all love her and it breaks my heart but she's attacking everyone :(