Right now im living at my mother-in-laws house until we find a new place. I have 2 super friendly cats that live with us, and my MIL just got a new Chihuahua/teacup yorkie mixed puppy! My younger cat, Pikachu, doesnt mind the puppy but he

does run away if the pup gets too excited. My other cat, Rorschach, wont come up from the basement! I even tried to carry him upstairs to let him hang out in our bedroom but he started hissing which is not normal for him at all. Any suggestions on how to help them get along? I dont want Rorschach stuck in the basement 24/7!