Noticing the Fourth Wall

""I see it all now! There's a reason we're all weirdos who make strange food! We're in...a CARTOON!""

- Chowder

A specialized form of Breaking the Fourth Wall. Fictional characters suddenly come to the realization that they are fictional characters living in a work of fiction. As you can imagine, this is often a terrible shock. How would you take it if you suddenly learned that you, your family, your friends, and your entire universe are all fake, and that everything you've ever said, done or thought was the product of someone else's imagination? Thus, characters who experience this trope seldom take it well. Popular in comic books and among writers who want to wax philosophical.

Not to be confused with Truman Show Plot, in which the characters are real, but the world is fabricated.

Anime and Manga

 * The Big O: You may not be able to tell by the confusing finale, but this was the true secret of Paradigm City:
 * Fushigi Yugi is about a girl and her best friend reading a book who get teleported into the world of the book.

Comic Books
"Homer: If I don't exist...does that mean I can't eat doughnuts?"
 * The sci-fi comic 2000 A.D. once ran a Mark Millar comic about a man who suddenly realizes he's in a comic, and it will soon end. He decides to make the best of his time left by going in a nihilistic rampage ("It's not really murder, you understand. None of these people have names.") It ends with the man being arrested and pointing the reader out to one of the policemen. He turns around in horror, screams, and grabs on to the panel border with tears in his eyes. "Oh God! Please don't turn the page...Please, read it again!"
 * Brian Azzarello would later pay homage to this story in his Doctor 13: Tales of the Unexpected miniseries.
 * This was also parodied in a Simpsons comic book, where Sideshow Bob revealed this fact to his prison guards. The scene ends complete with panel-grabbing.
 * A common epileptic tree is that this is Joker's reason to behave as crazily as he wishes.
 * Grant Morrison's Animal Man often goes to "Comic Book Limbo," where all the no-longer-used comic characters live, and meets his creators. But whenever he leaves, he loses all memory of the visit.
 * Grant Morrison was punished for this by having his Author Avatar (codename: The Writer) drafted into The DCU Suicide Squad.
 * Superboy-Prime from DC Comics flips this around. He loses the real world (ours) and ends up going more then a bit nuts in the realms of comics that used to be fake to him.
 * The Simpsons "Treehouse of Horror" comic "Immigration of the Body Snatchers" ends this way. After a parade of Shout Outs to twist endings from The Twilight Zone, Planet of the Apes and even Monty Python, Sideshow Bob shouts that none of it is real and they're all just ink on paper. Everyone laughs at him...until he points to the surrounding panels and to the reader.

Literature

 * A couple of characters in the later Dark Tower books by Stephen King do this. Callahan angsts over it while some get pissed at the author for killing off their friends.
 * The whole point of the Elephant and Piggie book, We Are In A Book!
 * Pretty much the whole point of Sophie's World.

Live-Action TV
""It's like we're being watched. Like there was a wall missing from our apartment, like there were only three walls, and not a fourth wall.""
 * A Show Within a Show example from Star Trek: The Next Generation. The Moriarity character from a Sherlock Holmes reenactment miraculously learns that he's not only a fictional character but that he's a computer generated recreation of said character.
 * In a later episode he (Moriarity) does the same thing for his computerized girlfriend Regina.
 * In the Buffy the Vampire Slayer musical episode "Once More With Feeling" Anya notices the sudden lack of a fourth wall in their apartment:

"Sheldon: We're in a sitcom?!"
 * Parodied in a TBS commercial for The Big Bang Theory. Sheldon and Leonard are sitting in their living room trying to remember what show comes on before Conan on TBS. Before they can look it up, though, Conan O'Brien bursts into their apartment, looks at the Fourth Wall, and exclaims that the two can't learn that they're in a sitcom. Sheldon's response?

Newspaper Comics

 * The Dilbert strip for 10/20/2011 plays with this: After the Pointy-Haired Boss tells Dilbert to change lines on a page to dotted lines because they were "not made of ink," both glance toward the reader with comments about things they were not meant to know.

Video Games

 * Inquisitive Dave begins as a side-scrolling adventure game, but  he comes back with the knowledge that their entire world is just a video game, and this knowledge had given him the power to   This leads to  . After the credits, the creators reveal
 * This Let's Play video explains that
 * One of the dream sequences in Max Payne has Max realize he's in a comic book/computer game. In the course of the dream he observes that each of these revelations are "Funny as hell, it was the most horrible thing I could think of." Upon awakening, he says that the drug-fueled dream left "dark stains on my soul that would never come off." As a confirmation of this, he observes in the game's sequel that "when I slept, my dreams were nightmares."

Web Comics

 * The entire premise of the webcomic Kid Radd.]] The title character already knew he was a video game character being controlled by a player, but still had no idea there was a universe beyond his game.
 * All of the characters in 1/0 know that they are fictional and constantly Contemplate Their Navels, pondering subjects such as whether they exist and whether they will continue to exist after the author stops writing the comic. However, the comic has No Fourth Wall to speak of.
 * Eyebeam has a version that was combined with All Just a Dream, these three strips.
 * Deconstructed in Captain SNES, where video game characters Touched by a particular Eldritch Abomination realize that they're video game characters... and don't take it well at all.
 * An Xkcd strip features this, when the subject of this man's daydream realizes the truth and it all goes Off the Rails.
 * Done in this Sinfest comic.

Web Original

 * One of the proposals for the nature of SCP-001 is that

Western Animation

 * The above quote from Chowder, who is able to notice it because an overdose of "Brain Grub" grants him superhuman intelligence. He then uses his mental powers to make the show smarter, turning it into a boring intellectual program.
 * Fairly Oddparents: When Timmy wishes the Crimson Chin out of his comic and shows him he's fictional, he suffers a Heroic BSOD. When he's returned to the comic, every panel is just him sucking his thumb in a fetal position.
 * The Genre Savvy Deadpan Snarker Digeri Dingo from Taz-Mania has more fun with the fourth wall than any other character in the show. Subverted as he's not very concerned that he lives in a fictional cartoon.
 * In Toy Story, Buzz Lightyear finally realizes he's a toy when he sees a commercial advertising him. This probably counts as an in-universe example, because what he doesn't realize is that he's a CGI animation.