There's a dinosaur on the 13th floor

"Welcome to the Sharemore Hotel," said the porter. "You must be Mr Snore. Let me show you to your room..." Mr Snore checks into a hotel room, only to discover that the room is already occupied - by a mouse! So the porter moves Mr Snore up a floor to a new room. Alas, that room seems to be occupied by a fuzzy critter, too. Up thirteen floors, one floor at a time, Mr Snore gets moved and moved again until the porter has run out of options for his guest. Why? Because there is absolutely no way anyone should EVER go to the top floor, the 13th floor, in the hope of finding room and rest...