I adopted a kitten a few months back from the SPCA (he's about nine months old now). He is very much litter box trained, has been since day one. The problem is that when he gets mad at me or anyone else he pees on something, usually my bed, but he's also peed on the couch, my mother chair, and the floor. Yesterday, my parent's had a party so they locked him in my room for six hours (I was in the room, avoiding drunk people), so no sooner than I fell asleep last night (this being after everyone had left, when my door was open) he pees on my bed. A week ago he did the same thing because I left for a few hours, and before that because we (me and my parents) were out in the yard for a few hours and he's not aloud outside. His cat box is clean, and he uses it every time except when he's mad at me for something. I can't just lock him out of my room at night because he'll pee on something else instead, or wait until during the day when my doors open to pee on the bed. I love my cat, but he's really pushing his luck. He is neutered, he's an only cat, and he seems to know he's not supposed to do that because he hides afterwards. Please, some advice? Anything?