sudden cat behavior change

Question
Hello.  I have a mostly Russian Blue cat (parentage is not 100% known) that I've had for 3 years (since the age of 6 weeks).  I've always been very affectionate to him and given him plenty of attention.  Play has always been lively.  We "chase" each other and provoke each other often.  He will arch his back, puff up his tail and walk "sideways" when doing this and has never shown an abundance of fear or aggression.  Tonight, for the first time in 3 years, he moaned, growled and hissed at me during one of these play sessions.  This continued all evening until I took a shower. He seemed to be genuinely afraid for no good reason.  He's on my lap right now (as he normally is) and everything seems fine.  Nothing has changed in his diet, his litter, water, etc.  Any ideas on what could have caused this sudden and unprecedented fear of me, his owner who loves and cares for him? :)  Could I have possibly brought home a smell that repulsed him until I showered this evening?  I can't speculate on any cause or effect here.  Any insight would be much appreciated.

Answer
John,

Sometimes only a cat knows why he does something! It sounds as if you did bring home a new smell or wore something he didn't like or didn't associate with you.

It may have been an isolated incident. If the behavior continues then I would take him to a vet for a checkup. A cat doesn't change behaviors suddenly without a reason. Pain would cause him to behave like that.
If it continues I would first rule out a medical issue causing it before addressing it as a behavioral problem.

Hopefully it won't happen again, but if it does and he checks out OK with a vet, then write again and we can go from there. You may also want to call a breeder of Russian Blues and find out if it is a possibility that his behavior is something that is specific to that breed.

Merry Xmas!
Carol