I have 5 cats....3 are 8 yrs old and brothers and sister....the problem is Mike and Scooter...they are brother and sister..Mike is a male and he is the only one that goes outside..but NOT in the winters...so he has been bascily house bound since Nov...Scooter is female....100% indoor cat...Lately Mike has been attacking her...last night they managed to knock over a litter box....and a plant that was on the fridge...I have NO idea why he is going after her like he has been....It goes on for a bit then it seems to stop but lately its been every few weeks...I have some rescue remedy and put it in their water but its not stopping the attacks...And as most of you know the worst sound in the middle of the night...wakes the whole house...and he did it again this morning...so I thought well its nice outside I put him out but he just sits on the steps til I let him in...I thought going out might do his some good....Scooter is walking around on egg shells ..I'm at a loss on what to do to stop this...Any suggestions ?