Buddy used to go missing on me in the house as well. I think he is a Houdini cat like Noel and Ritz. He doesn't do this very often any more but he will get completely under the covers on my bed or Rachael's bed and will make himself so compact that you do not see him. I don't know how he can breathe in there but he does. A couple times I have gotten into my bed at night only to hear a meowrrarrrr because I sat or laid on him!