Just as the title says...
So I know that you can't really answer this without seeing him and if you're not a vet. But this afternoon I am at the end of my tether.
I have a nearly 2 year old indoor Russian blue cat who has suddenly started rubbing and biting on on me like a wild cat.
There is no obvious injury and he is eating drinking and using the litter tray as normal but keeps having mad aggressive attacks trying to bite me. It doesn't matter if I play with him or ignore him 
I'll have to call the vets tomorrow but I wondered if anyone had any magical ideas 