The Rules of Imaginary Worlds

Magnus sometimes doesn't like to go to the toilet.  He'll ususally go if you tell him there's fish in the toilet, or spaghetti, or cars.  

He's in playschool, and he doesn't want to go.  I tell them there's fish in the toilet, he still won't go.  He asks if there's a helicopter in the toilet, and I tell him of course there is.  He happily goes to the bathroom, opens the toilet, looks in, looks at me and says, "There's no helicopter in here."