I've had this 2 year old(M) for about 3 months now. He was never supposed to be a permanent resident as I took him from a coworker(who lied to me about his behavior btw).I took him so he wouldn't have to go to a shelter and planned to find someone else to take him. Well now i'm kinda stuck with him because no one wants a cat around here. The main problem right now though is no matter what I've tried he won't leave my poor older cat 11(F) alone. He will stalk her, pounce on her and try to fight with her no matter what. I have tried the feli-away collar and spray. Yelling when he gets near her and a water gun, but he is relentless and wont leave her be. Now I have to keep them separated at nearly all times, because when he notices I'm not paying attention he lunges at her. Then she just starts this awful screaming just wanting to be left alone. I try to play with him and wear him out, but it doesn't work either. What can I try? They are both fixed. I'm very close to just giving him up to a shelter myself now. Tried to do a nice thing, but got lied to and feeling burned by a coworker.