kas, From reading your last post, I have seen this type of behavior before. If one cat lashes out at another one, for no apparent reason, this action somehow alerts the other one to fend for him/her self, and thus begins a series of this-for-that reprisals, eventually developing into an full-blown "civil war" between the two of them. I don't really know how to stop this behavior pattern after it begins. Sometimes, they age out of it, but more often there is a lingering distrust between the two of them. The only remedy I can suggest is to try to stop the original aggressor at first attempts, with some kind of "cattitude corrector". Possibly a spray-water bottle.

........wayne