When characters breach internal fourth walls to go on adventures in books, films and so on. Generally they travel into one or more books or films to become part of the plot, or, at least, to observe the plot first hand. This often forms part of an allegory or metaphor for escapism, the idea that the imagination allows a reader to 'enter' a work and subconsciously cast themselves as an observer or a main character. This is one reason why the lead characters of books are often very vaguely or loosely described, allowing the reader to assume their identity as a form of role-play.