Everybody knows about the 4th wall, but not many people realize there are more than just four. The first three all have to do with characters within a story interacting, and the fourth is the author and character interacting, but there are even more than four. The one to be discussed here is the fifth wall, the barrier between different fictional universes. This wall prevents events such as Superman showing up in a Stephen King horror novel. As you can imagine, it's quite useful, otherwise characters would be running willy nilly all over the place, with little regard for copyright laws.¹⁾

On Improbable Island, the 5th wall is breached with such great frequency Horatio had a revolving door installed, which saved him a lot of req in getting it fixed each time. Notable perpetrators in these events are Skidge, XaNe, and generally about half the population of the Aleatory Ensemble.²⁾³⁾