My female cat Thunder does that too we have 4 cats and we know shes the one doin all the mess we have even see her. She will even do it right in front of you. She will pee all the tile right when everyone is in there. and she like poops every day on the steps. My mom whats to just get rid of her. she wont stop doing it. Shes fix and shes started maybe about 4 months ago and she is 3 years old. any suggestions for what i should do i clean the litter box right after they use it, but thunder choses not to use the box? what should i do im desperate!!!