cat becoming aggressive... need help

Is it odd for a once shy feral to become nasty all of a sudden??

He has in the last week hissed at me twice and this morning he attacked a poor sweet cat just sitting htere waiting to eat (he took off and i didnt come back).

I had written before aobut the tom cat doing this. He has calmed down a lot and since being sick and letting me touch him - he of course stopped hissing (which I believe only happened once).

I know these cats should only hiss if they feel threatened - but I havent been THAT close to him (i actually ignore him - not looking at him - just hear hissing and see he is looking at ME!) and he has plenty of space to back away. I am fearful of this attitude.

I noticed also his eyes were dilated after attacking the cat (im assuming this is normal - but it did freak me out a bit).

My main question is the tom cat usually goes after this guy (the weird thing is they will eat together after - which i dont get). I have been stopping these attacks by tapping hte tom. Should I just allow him do it - maybe put this other cat in his place????? The tom did start to go after him this morning after he attacked the shy one - but i stopped it.

THANKS>>>>

I want to make sure I have this straight - there are the cats, The Tom, The Attacker and The Shy One. Right?

Possible that either he or the Shy One is sick. If its him, he's not feeling well; if its the Shy One, he probably isn't tolerating the smell of the sickness very well. He's wound up about something (the dilated pupils).

The Tom may be keeping everyone in their place. I am really not sure because I'm not sure if I have it right about there being three cats.

Sudden aggression means a couple of things to me: the aggressor is sick, an unneutered tom is trying to take over his territory and he is threatened, or the females in your area are starting to go into heat. It is a little early for the spring kitten season heat (usually starts mid February), but you can't rule that out.

Is everyone you know of fixed?

Yes you have it right - 3 cats and they are all neutered.

there MAY be one cat that is not fixed (not in the 3). I took it to be neutered and they said the ear looked clipped. (I didnt keep the BEST notes on the cats - but I was so sure this cat was never altered.)

Heres a new question - is it possible for cats to be born with uneven ears?? its a young cat and the tip of one ear is slightly smoother than the other.

thanks for the help.... so should I let the Tom continue to keep things in order instead of interfering????