About a year ago, we introduced little 8 week old Simi to my 14 yr old Midnight. While they have never been the best of friends, they, after a few weeks, have been tolerant of each other. Today I am not sure exactly what happened but it ended with Midnight under the bed and Simi under a laundry basket, a LOT of furr on my kitchen floor and some very blood battle scars for the cats and members of the household. Is it normal for 2 cats to suddenly have issues with each other? I am scared to put them back together again for fear of their next battle.