Even though clues point to the contrary, a dragon reassures the reader that there are no actual dragons in the book.

"Andy and Terry live in a 169-story treehouse. (It used to be a 156-story treehouse, but they've added 13 more stories.) It now has a kangaroo-riding range, a whatever-weather-you-want dome and a hall of funhouse mirrors--the perfect place to hide from the truancy officer who is trying to catch them and make them go to school! Unfortunately, the hall of funhouse mirrors is also the place where their evil trouble-making twins, Anti-Andy, Terrible Terry...