My Cat Has Completely Lost It- Cat Fights
I need help. First of all, let me introduce my cats. Mattie is five years old, female, fixed and has never been an outside cat. We have always kept her inside. When we first brought her home, she was very loving and happy and purred. She wanted all kinds of attention and liked to be sitting on my lap or chest or whatever. We brought another kitten home about a year after we'd had Mattie and introduced them. They got along famously, but Mattie was never the same with my husband and I. It was like I'd betrayed her by bring another cat into the house or something. She just didn't come around like she used to. We eventually had to get rid of Salem, but we brought Figaro into the house before Salem left. Salem and Figaro got on wonderfully, but Mattie and Fig never really liked each other. Figaro is three years old, female, fixed and was an outdoor cat for the first six months of her life before we brought her home. She has always been a good cat. She has been a little strange (read: brings me gifts of shoes, socks, cat toys, etc.) and very clingy with me and not at all with my husband, but good overall. Mattie and Figaro tolerated living in the same house, but they were never "friends". They sort of lived in an uneasy peace. But if Figaro ever got too close or anything, Mattie would hiss at her and leave the area. The only exception to this was if they both had a similar interest in a room that was off limits or if they were eating wet food. But this worked for them. They never fought, although they chased each other sometimes, and Figaro has always been the dominant one.
Yesterday while my husband and I were cleaning the house, I opened the window of the basement where we live and let my cats explore the window well. Figaro was inside and Mattie was outside in the window well sniffing around and stuff when Fig launched herself into the window well and straight up attacked Mattie. Mattie fled with Fig in hot pursuit and she chased her up and down the hall three times before stopping. Figaro also peed the whole way from the window back to our bedroom. I've never seen her do anything like that before. Then she howled and whined and was breathing weird. Ever since, they've been fighting like they haven't lived together for the last three years and Fig is acting crazy, almost feral. She hisses at my husband and sometimes at me, which she's never done before now. They had another crazy fight when Mattie finally ventured out from under the bed and again in the middle of the night. Now Mattie is basically confined under the bed while Fig roams around and clings to me. I have no idea what triggered this or how to solve the problem, but if it continues I may just have to get rid of Figaro. It's like she went crazy. Any ideas or solutions?