I have to recommend bruisedhips and godforesaken as houseguests. They depart immediately into their room and go to sleep every night at 10. In the morning they slip out of the house before they can be observed, and don't return again until it's time to sleep. It's hard to get them to eat your food, and sometimes it isn't clear whether they've actually been in your house. If you accuse them of these things and try to get them to behave like normal guests (eating your bagels, watching TV, clonking around being bored) they get a wild-eyed look and accuse members of your family of being shape-shifting cat demons.
In all seriousness it was great to have them visit, and I did get them to eat my rice and hummus at one point. Come back soon, y'hear?