In Show A, you watch TV. In show B, the TV watches YOU. This is a special kind of crossover trope in which the characters from Show A will enter the universe of Show B—both shows of which are "real" to us. In other words, neither is a Show Within a Show. In addition to finding out that they're trapped in the universe of Show B, the characters of Show A discover that they themselves are the subject of a Show A in the universe of Show B. The characters from Show A are, in essence, simultaneously Trapped in TV Land and a Refugee from TV Land. This isn't Real World Episode, since both universes are depicted as being equally "real".
A situation in which Show A is fictional in Show B and Show B is fictional in Show A isn't an example of this trope if they never share a continuity; if in A's continuity B is just fiction and vice versa. This could happen with two completely unrelated works that each incorporate real world elements that happen to include the other work.
Strictly speaking, this kind of crossover should never logically be allowed to exist. At the very least, the particular episode of each series or work which references the other should be assumed to not exist within the other's universe. Otherwise, you would have a situation wherein it would be distinctly possible for the main characters to see the TV show of their entire reality within said reality, realize their entire existence was a lie, and freak out. And we wouldn't want that, now would we?
One possible justification would be if the two worlds are simply Alternate Universes and the "shows" in question are based on visions people have from the other world. In this case, expect the characters trying to establish what in this show is correct and what is not. It could also be the case that the creators of Show B, within the universe of Show A, simply decided to set Show B in a world where the main characters of Show A don't exist, but acknowledge their impact by making them fictional instead- though this explanation breaks down if the world at large, and particularly the media, shouldn't know about the events of Show A in the first place. Unfortunately, the Fiction Identity Postulate proves that all fiction is equally unreal. And anyone living in an Alternate Universe may be, by definition, fictional.
See also Celebrity Paradox. Comic Books Are Real is a one-sided version, usually dealing with a Show Within a Show instead of another real-life series. Compare Faeries Don't Believe in Humans, Either, where each side believes the other is only stories prior to meeting, but both have always been fact and that's what the stories are based on. Contrast Stable Time Loop, which leads to a similar Ontological Paradox.
- Martian Successor Nadesico:
- Excel Saga featured a kid who drew forged key frames from the Show Within a Show Puni Puni Poemi. The show was Defictionalized, and in Puni Puni Poemi, a math problem in school involves the number of cels used in each episode of Excel Saga.
- Once upon a time, Milestone Comics and DC Comics' Superman books participated in a Crisis Crossover, Worlds Collide. The story started with a mailman in the DC Universe who went to sleep and dreamed of waking up and working as a mailman in the Milestone universe (or vice versa), until other strange things started happening in both universes. The Blood Syndicate (essentially a streetgang with powers) were the first Milestone characters to meet Superman, and although they thought he was just a local wannabe, they all immediately knew who Superman was, what he could do, etc., because Superman was a comic book character in the Milestone 'verse. ("Does your mama know you left the house looking like Clark Kent?!"note ). Superman doesn't have the same benefits, realistically, since the Milestone Comics characters were hardly a household name, and he's not much of a comic fanboy. As the mailman develops into a Reality Warper, and reveals that he was an Ascended Fanboy of comic books, both the Milestone and Super-family characters start to believe that the other universe was created by the mailman's powers, which complicates their efforts to stop the new supervillain.
- Static, an Ascended Fanboy, lampshades this; he drops his knowledge of Post-Crisis Superboy's history, and explains "I read all your comic books! Don't you read all of my comic books? (Do I have comic books?)"
- In the wake of a Cosmic Retcon, the two universes have now been merged with a new, shared history. Only a handful of people (including Superman) remember that they were ever separate.
- This happens to Superman a lot; it used to be that DC/Marvel crossovers operated under the conceit that the characters, if they didn't know of each other, at least operated in the same reality for the duration of the crossover (Spider-Man/Batman, for example), but after DC vs. Marvel/Marvel vs. DC, they were explicitly separate realities. It is true that the Fantastic Four knew of Superman from the events of that crossover in Superman/Fantastic Four, it was also established that Ben Grimm and Franklin Richards knew of Superman from the exploits of his comic book counterpart, and watch Superman: The Animated Series. Incidentally, Marvel vs. DC played with a retcon of Spider-Man/Batman when the Joker recognized Spider-Man from somewhere. Of course, since S/B was set before the Spider-clone saga and DC vs. Marvel was set during it, Ben Reilly didn't recognize the Joker from Peter Parker's adventure.
- Pre-Crisis at least, Earth-Two was fictional to Earth-One, which is why the writers had to create the multiverse so that Barry Allen could have a crossover with Jay Garrick. In Barry's first appearance, he mentioned how Jay was his favorite comic book hero, but lamented how the Flash was merely a fictional character. In a later story, Barry travelled to Earth-D where he was a fictional character and the local version of the Flash, Tanaka Rei, grew up idolizing Barry Allen and reading Barry's adventures in comics just as Barry had grown up reading Jay's comics.
- The first Futurama/Simpsons Bongo Comics crossover comes about as the Brainspawn zapped the Planet Express crew into an old Simpsons comic. The second has the Simpsons characters and later, many other fictional characters materialising into the reality of Futurama from a comic by one of Farnsworth's inventions. However in their Bongo Comics crossovers, The Simpsons are pointed out as the fictional ones in Futurama's "real" universe. It should be only one way, being built off the idea in "The Day the Earth Stood Stupid" where the Brain can take people into worlds of fiction but since Matt Groening cameos on The Simpsons as the creator of Futurama...
- Terra Obscura. Their science heroes are the stars of comic books in Tom Strong's world, and vice versa.
- Jimmy Olsen in Superman comics is a fan of the Spin Doctors, a band with a Superman-inspired album and a song about Jimmy Olsen.
- Lampshaded in The Multiversity #1 by Captain Carrot, as the Superman of Earth-23 reads a copy◊ of Action Comics v2 #9:
"I always suspected that one world's reality is another's fiction. That's why I like happy endings!"
- A four issue miniseries had Mr. Mxyzptlk and The Do-Do collide in interdimensional transit and conspire to cause mischief by mixing up their worlds. Superheroes recognize the Looney Tunes from their cartoons, and Foghorn recognizes Clark Kent as Superman because he's "had a subscription to Action Comics since [he] was an egg." The whole crossover ends with Clark reading a Looney Tunes comic at the Daily Planet, where Perry White has just found the singing frog - all of which is seen by Bugs Bunny, who's reading a DC comic.
- Fan Fic author Jared "Skysaber" Ornstead used this trope to invert the Self-Insert Fic trope of Author Avatars knowing everything about the worlds they visit; there's always a Show Within a Show based on his life in each one, and at least one of the characters is guaranteed to be a fan.
- In the Harry Potter and Fate/stay night crossover Fan Fic "Fictional", Harry is a servant created by Caster from the book series. A big part of the plot is Harry coming to terms that all of his hardships were fictional and how to deal with it after the obligatory freak out. And you know, deal with being a slave (*cough* Servant). He also has to hide his scar, because other people freak out when they meet Harry Potter too.
- The Infinite Loops actually justifies this trope. The admins responsible for repairing the multiverse store backups of universes wherever they can, which has the side effect of making the natives write fiction about that universe. The Hub universe is simply the most well protected and undamaged area, which is why we have all this fiction....
- In the first chapter of Walking in the Shadows, D'hoffryn brings Xander to Smallville to have a chat. During the conversation, he mentions forgetting that both are fictional in the opposite universe.
- Played with in M. McGregor's The Wonderland Subject, a dimension-hopping Buffy the Vampire Slayer / Ultimate Marvel crossover in which each universe has fiction based on the other one. Xander and Jean Grey spend quite a while being fannish at each other.
- In Kyon: Big Damn Hero, characters make several references to Lucky Star — which, in turn, contains many references to Haruhi Suzumiya.
- Within Sherlock BBC fanfiction, Doctor Who has been both fictional (e.g. John Watson's a whovian) and real (e.g. John is the son of Captain Jack Harkness, a character on Doctor Who), depending on what universe the fanfiction author is writing in. Additionally, some Whovian fanfiction features the Sherlock characters as real people, or claims that the Doctor is a fan of the original Conan Doyle figures. *Cue Rift crack*
- In Origin Story, Xander used to read Marvel Comics and in the Marvel Universe, Buffy the Vampire Slayer was a fairly popular show though it only got two seasons and had a different cast (All of whom are a Mythology Gag from original casting ideas).
- My Hero Playthrough: Canon!Izuku and Bakugou appear as Bosses in a Reflective Dungeon. An Omake in the same chapter has canon!Izuku experiencing the fight as a dream, commenting on the oddness of seeing Momo wearing "biker's leathers and a helmet", and fighting Sailor Mercury and a girl wielding electromagnetic powers that Shoto (of all people) identified as Mikoto Misaka from the RailDex series.
- It happens in crossover Echoes Of Yesterday. In Earth-Bet, both DC Comics and Marvel Comics exist. Taylor Hebert used to believe their heroes were merely fictional characters who fell out of fashion several decades before her time, until she is rescued by one. When she expresses bewilderment at the fact that she's been saved by a comic-book character, Kara replies the Multiverse is infinite and Taylor life's history is guaranteed to be a fictional tale in other parallel realities, including her own universe.
- In Fairy Tail Redux: Salamander's Time Traveling Escapades, Fairy Tail's characters are fictional in the Rave Master, Animal Land, JoJo's Bizarre Adventure and When They Cry universes, and vice versa.
- In the first scene of Scream (1996), the film Halloween (1978) is the subject of one of the questions the killer asks, and later Halloween is shown at a party (with one character loudly protesting at the mistakes Laurie Strode is making). Likewise, in the Halloween sequel, Halloween H20: Twenty Years Later, a couple of characters are watching Scream 2 in one scene.
- In Jay and Silent Bob Strike Back, the duo stumbles upon the the filming of a Scream movie. The first movie in the series had a poster for Clerks, a movie in the same continuity as Jay and Silent Bob. Though it's not explicitly stated to be a Scream film, it could have been a Stab movie, as some fans think. Made more complicated when Jay and Silent Bob make a cameo in Scream 3.
- In A Nightmare on Elm Street 3: Dream Warriors, the TV-obsessed patient is seen watching an early scene from the movie Critters. Later, Critters 2: The Main Course had one of its alien doppelgangers attempt to imitate a cardboard Freddy Kruegar standee at a video store.
- In the first A Nightmare on Elm Street (1984), The Evil Dead (1981) is seen on a TV, a Shout-Out to a poster for Wes Craven's earlier film The Hills Have Eyes (1977) appearing in The Evil Dead (which was itself a Shout-Out to a poster for Jaws appearing in The Hills Have Eyes). Then in Evil Dead 2, Freddy Krueger's glove is seen in the shed where Ash creates his chainsaw-hand. Averted in the comics, there was an Ultimate Showdown of Ultimate Destiny between Freddy, Ash, and Jason.
- In Independence Day a character makes a passing reference to The X-Files, conversely, in the first X-Files movie we see Mulder urinating in front of an Independence Day movie poster.
- The major plot point of The Frame is two characters in two different tv shows discover that they can talk to each other through the television. They also realize that The Plot Reaper is coming for them in each show.
- In the second Die Hard, at one point an episode of The Simpsons is being shown on TV. In a second-season episode of The Simpsons the following year, the family is shown watching the original Die Hard.
- From Through the Looking-Glass:
"What ... is ... this?" he said at last.
"This is a child!" Haigha replied eagerly, coming in front of Alice to introduce her, and spreading out both his hands towards her in an Anglo-Saxon attitude. "We only found it to-day. It's as large as life, and twice as natural!"
"I always thought they were fabulous monsters!" said the Unicorn. "Is it alive?"
"It can talk," said Haigha, solemnly.
The Unicorn looked dreamily at Alice, and said "Talk, child."
Alice could not help her lips curing up into a smile as she began: "Do you know, I always thought Unicorns were fabulous monsters, too! I never saw one alive before!"
"Well, now that we have seen each other," said the Unicorn, "if you'll believe in me, I'll believe in you. Is that a bargain?"
"Yes, if you like," said Alice.
- Robert A. Heinlein's The Number of the Beast introduces the concept of the "World as Myth" which supposes that all fictional universes are equally real and, moreover, are accessible to one another via interdimensional travel. The act of authorship is what creates said universes, which leads to the interesting notion that the characters in any given universe may be controlled, at any given moment, by an Author from another. Or that characters could, in theory, meet their own Author. The novel concludes in a Massively Multiplayer Crossover whereby the protagonists host a convention of characters from nearly every Science Fiction and Fantasy universe ever.
- The subsequent novels The Cat Who Walks Through Walls and To Sail Beyond the Sunset run with the concept to its logical conclusion, in which the characters wage running pandimensional battles against groups of agents from other realities, all competing to see which can rewrite history to their whims.
- Philip K. Dick The Man in the High Castle contains a Subversion. The novel is an Alternate History describing a hypothetical timeline in which the Axis won World War II and conquered the United States. And in the novel's 'verse exists another novel The Grasshopper Lies Heavy, which is itself an Alternate History novel describing a hypothetical timeline in which the Allies won WWII, but which is not our reality. For example, in it, the British Empire is the dominant global power.
- Scots author Quintin Jardine has written two long-running series: Skinner, about a high-ranking Edinburgh police detective, and Oz Blackstone, a private detective and part-time actor. In at least one Blackstone novel he is involved in making a film based on the Skinner books, while the Blackstone novels themselves appear in Skinner's world.
- The Goosebumps series had a recursive fiction paradox. For example, a couple of the main books and a lot of the Choose Your Own Adventure books mention the main character having read about something like their situation in a Goosebumps book. In a good deal of the Give Yourself Goosebumps books, you need to know about the book being referenced to get a good ending!
- The SF novel "Worlds Apart" by Richard Cowper is a particularly tricky case. A invented B and B A, but at the end both universes merge.
- In Terry Pratchett's The Science of Discworld, the wizards create a universe containing 'Roundworld', where physics works but magic and narrative logic don't. The computer Hex tells them not to destroy it because "Recursion has occured".
- Okay, this gets complicated: In Jasper Fforde's Thursday Next book Well of Lost Plots, Thursday is hiding out in the Bookworld, in an unpublished crime novel called Caversham Heights, along with two Generics, one of whom takes the form of Lola Vavoom, an actress frequently mentioned in the Thursday books. At the end of the book, Caversham Heights becomes a sanctuary for nursery rhyme characters, turning into a nursery rhyme/crime novel mashup. The Nursery Crime books are supposed to be what Caversham Heights becomes, and The Big Over Easy mentions that that version of Lola Vavoom has a backstory that includes appearing in an adaptation of The Eyre Affair.
- Mexican shows El Chapulín Colorado and El Chavo del ocho recursively reference each other at different points, and they eventually got a crossover where the El Chavo characters believe Chapulín is only a fictional superhero and are surprised he really exists, there's also jokes about how Chavo and Chapulín are played by the same actor.
- There was a crossover between Power Rangers and the live-action Teenage Mutant Ninja Turtles series. It's particularly amusing when one of the turtles laughs off a mention of the rangers as comic book characters.
- An episode of The Twilight Zone (1959) entitled "A World of His Own" somehow managed to do this to itself. The story deals with a writer named Gregory West who can cause fictional characters to appear in real life if he dictates descriptions of them into his tape recorder, and cause them to disappear again by burning the tape he described them on. At the end of the episode, as is traditional Rod Serling appears to give the story's closing narration.
Rod Serling: We hope you enjoyed tonight's romantic story on The Twilight Zone. At the same time, we want you to realize that it was, of course, purely fictional. In real life, such ridiculous nonsense could never...Rod Serling: ...Gregory West: I mean, you shouldn't say such things as "nonsense" and "ridiculous! [takes out tape labeled "Rod Serling" and throws it into the fire]Rod Serling: [resigned] Well, that's the way it goes... [vanishes]
- In Mad About You, there is an episode where Paul visits an old apartment of his. That apartment happens to be across the hall from Jerry Seinfeld's and he runs into and has a rather poignant conversation with current tenant Kramer. But in a later episode of Seinfeld, George is forced to suffer watching an episode of Mad About You with his fiancee Susan.
- Doctor Who is fictional in EastEnders: they have a character who is a fan (Bradley) who even goes to a Doctor Who convention at one point. EastEnders is also fictional in Doctor Who wherein Jackie Tyler is a fan, and EastEnders appears Show Within a Show style in "Army of Ghosts". The Doctor also references it in "The Satan Pit". There was a crossover between them in 1993 for Children in Need. In "Dimensions In Time", neither show acknowledges the other's fictionality in it and it isn't considered in continuity for either (one explanation touted by Doctor Who Spin Off Media is that it was All Just a Dream of the Seventh Doctor).
- Sherlock does this in "The Abominable Bride", which is set up as an Alternate Universe featuring the modern-day Sherlock characters in the Victorian setting of the original Sherlock Holmes novels, before revealing the whole thing is taking place in modern-day Sherlock's head as he tries to figure out how Moriarty could still be alive. But the end cuts back to Victorian Sherlock and John, and Sherlock speculates on what their lives would be like in a hypothetical future... his descriptions, of course, matching the modern-day adaptation exactly.
- References to characters watching Passions started showing up during season four of Buffy. Shortly afterward, Passions characters started watching Buffy. Also, characters in Buffy have talked about Xena: Warrior Princess, whereas, while they clearly can't have a television show on Xena, there is a play called 'Buffus the Bacchae Slayer'. Of course, as Xena is both told by a literary agent and fictional within itself, it's anyone's guess as to what is actually going on.
- Sort-of real life example - the series Bones is inspired by the work of author Kathy Reichs. In the series, the heroine is an author who writes novels about a character named Kathy Reichs.
- The novel character seems very close to the author in personality, though the events of each plot, per Reichs' afterwords, are only based on the broadest strokes of real-life cases. The television character is almost completely different from the novel character. It's really just the names.
- Dr. Temperance Brennan gets a honorable cameo appearance in Fforde's Thursday Next series, which runs on recursive fictionality.
- A tricky one: Green Acres coexists with Petticoat Junction, and Petticoat Junction coexists with The Beverly Hillbillies, but Beverly Hillbillies is fictional on Green Acres (and is Eb's favorite show).
- In one episode of Green Acres Eb even watches an episode of Petticoat Junction.
- Leverage and Psych are both mentioned as TV shows in each other's universes, but unfortunately, that leads to a What Could Have Been, because if Psych hadn't made Leverage fictional in their universe, Word of God says that Leverage's Eliot would've had an uncle named Henry.
- Batman (1966) and The Green Hornet present a particularly snarly version of this trope:
- An episode of The Green Hornet establishes that Batman is a (presumably fictional) television show in his continuity.
- Likewise, in the Batman episode "The Impractical Joker," Bruce Wayne, Dick Grayson, and Alfred are watching a news program about how Batman and Robin were made helpless by a new Joker device earlier in the day. In disgust, Bruce asks Dick to change the channel, noting that The Green Hornet is about to come on. We don't get to see any of that, as Joker breaks into the TV channel's signal to gloat and taunt Batman over the airwaves.
- Yet, The Green Hornet and Kato appear as a "Batclimb Cameo" - a regular occurrence where Batman and Robin are climbing a building and a celebrity or TV character appears to ask what they're up to. (Often this was used to plug other shows on ABC - including The Addams Family, Hogan's Heroes, and "The Felony Squad.") In that interaction, the Dynamic Duo greets the Green Hornet and Kato as fellow heroes from another city.
- After that cameo, the Green Hornet and Kato appear as "special guest heroes" in the Batman two-parter "A Piece of the Action/Batman's Satisfaction." This time, the Green Hornet and Kato are treated as villains - because that's what their public persona was in their own show - gangsters looking to get "a piece of the action" and end up taking down criminal enterprises from within.
- In The X-Files, a character is seen watching an episode of The Simpsons. Fortunately, it's not the episode where David Duchovny and Gillian Anderson appeared as Mulder and Scully. In Comic Book Guy's shop, one can see a poster to the X-Files movie.
- Eek! The Cat did an X-Files parody, and was also shown in an X-Files episode "Eve" where one of the little murderous clones watched the animation.
- Dr. House watches Gossip Girl and Blair Waldorf watches House. Leighton Meester, the actress who plays Blair, also guest-starred on an episode of House as a teenager in love with the titular character. In the 2011 movie The Oranges Hugh Laurie plays a man who falls in love with a friend's daughter... played by Meester.
- In Community Abed's favorite TV show is Cougar Town and in one episode he talks about guest starring on it. In one episode of Cougar Town Laurie and Travis watch the first season of Community on DVD. This eventually came full circle with Laurie and Travis as bit characters in the season finale of Community and Abed as a bit character on the season finale of Cougar Town. A later episode of Community had Abed, Meta Guy that he is, explaining the Mind Screw the whole thing had been for him.
- In Stargate SG-1, Jack O'Neill makes several references to The Simpsons, Richard Dean Anderson himself, being a huge fan. In season eight, Dan Castellaneta makes a guest appearence (even agreeing with Jack that Mr Burns is the perfect analogy for the Goa'uld). Just to make it more confusing, Anderson once appeared as himself in an episode of The Simpsons and, oh yes, they mention his work in Stargate SG-1.
- In The Flash (2014), Cisco has worn a rock-paper-scissors-lizard-Spock t-shirt, based on The Big Bang Theory, while Sheldon Cooper on The Big Bang Theory has worn Flash t-shirts and costumes.
- The plot line in Red Dwarf where the Dwarf crew realise they are fictional characters, and the only way for Dave Lister to escape the situation and re-assert independent reality involves going onto the set of a soap opera called Coronation Street, where an actor called Craig Charles plays a genial taxi-driver who is something of a laid-back, somewhat scruffy, Scouse slacker... it all gets eye-wateringly recursive after a while.
- In the episode "The Grasshopper Experiment" of The Big Bang Theory, Howard says that Raj's parents, who are doctors, probably love Scrubs, because it's a medical-themed TV show. In the episode "Our Driving Issues" of Scrubs, Dr. Cox says that he needs to watch The Big Bang Theory so that he can figure out why it's so popular.
- In the first episode of Class (2016), spin off of Doctor Who, April compares their school to the Hellmouth of Buffy the Vampire Slayer. In Buffy, Andrew mentions having watched every episode of Doctor Who.
- In the Doctor Who episode "The Tsuranga Conundrum", the Doctor's companion Graham says he's never missed an episode of Call the Midwife, while an episode of Call the Midwife set in 1964 had the main characters watching the contemporary Doctor Who serial "The Aztecs". (Sister Monica Joan finds it greatly exciting, the others seem more uncertain.)
- The Office sometimes makes references to various Muppet productions. One episode of The Muppets features Ed Helms as himself, and he mentions his role on The Office.
- In Atlus's 2011 puzzle game Catherine, Teddie from Persona 4 makes an appearance in the form of a figure on a bar table and a mascot on a beer bottle. The main character owns books called "Persona". A scene in Persona 4: The Animation shows that Yu Narukami changed his girlfriend's ringtone to the game over theme from Catherine. Later, in Persona 5, there's a PVC figurine of Catherine in Futaba's room, and one of the crane game prizes is a doll of a sheep man from Catherine.
- In a bit of Product Placement in Persona 5, the protagonist and party member Makoto can watch the Yakuza film, under its original Japanese title Like a Dragon. Makoto's text message extending the invitation even indirectly mentions the movie's real world director, Takashi Miike. In return, Yakuza: Like a Dragon has music from Persona 5's soundtrack that can be found in the game world and played on the jukebox at the party's home base. Both Yakuza and Persona are owned by Sega.
- Maniac Mansion has a Zak McKracken and the Alien Mindbenders poster in it, while Zak McKracken and the Alien Mindbenders has a Maniac Mansion poster in it.
- In Overwatch, D.Va's backstory is that she's a professional StarCraft player indicating that Starcraft is fictional in the world of Overwatch. Meanwhile, Heroes of the Storm is a crossover of all of Blizzard's franchises including Overwatch and Starcraft with all of the different franchises belonging to different universes in a shared Multiverse.
- The Way of the Metagamer and The Way Of The Metagamer 2: In Name Only. In Name Only makes the occasional cameo in the original, and it's been stated that the original exists within the world of In Name Only. Interesting in that In Name Only does not exist.
- Homestuck takes this trope to its Mind-Screw extreme with the events of the main story and the Midnight Crew. In the world of the main characters of Homestuck the Midnight Crew are from the latest MS Paint Adventures series, and the reverse is true for the actual members of the Midnight Crew in their world. However, Word of God along with recent events in the story claim that the the Midnight Crew exist within the same canon as Homestuck! In other words, it's not a Show Within a Show, it's a Show Within Itself!
- To elaborate on the "exist within the same canon", the world of the Midnight Crew is the same world as those of the Trolls, who also exist in (or at least communicate with) the kids in the Homestuck world, but are from an alternate universe.
- And, to take things even further, the art style and some of the universe mechanics for Midnight Crew suggest that it also takes place in the same universe as the previous MS Paint Adventures comic, Problem Sleuth.
- Also, Problem Sleuth was apparently in the same universe as Jailbreak and Bard Quest, and John in Homestuck has video games of all three of these. There are probably even more tie-ins than that.
- Like the time Jade read a panel of Homestuck, even being pretty true to what John had been doing at that point.
- The paradox is explained by the Author Avatar, who is likely sending different comics to different universes.
- To elaborate on the "exist within the same canon", the world of the Midnight Crew is the same world as those of the Trolls, who also exist in (or at least communicate with) the kids in the Homestuck world, but are from an alternate universe.
- A really subtle one with Questionable Content and xkcd. Marigold wears an xkcd shirt here, and this xkcd comic shows one of Hannelore's Twitter posts.
- Zero Punctuation does this with reality and the Standard Fantasy Setting. If we find fantastic adventures entertaining, fantastic adventurers find mundane reality entertaining (being how fantastic adventures is their day job and all). In one episode, an orc starts insisting that everyone call him "Alan" after a night spent browsing an Other Kin forum, and in another, a group of orcs is playing a Dungeons & Dragons campaign that revolves around accountancy.
- Inspector Gadget:
- In a few episodes the inspector can be seen watching Heathcliff and the Catillac Cats, likewise Inspector Gadget has showed up as a TV Show on Heatcliff. Both shows were produced by DiC at around the same time.
- Hector also dressed as Inspector Gadget during a Dream Sequence in a Halloween Episode.
- Hector and the other Cadillac Cats even appear in a cameo in one Inspector Gadget episode.
- A ridiculous example in the first season finale and second season premiere of South Park; "Cartman's Mom is a Dirty Slut" shows the characters see a promo for the movie "Not Without My Anus" and say they will watch it, and in the second season premiere, which turned out to be "Not Without My Anus" itself, Terrence and Philip flip channels and watch part of the former South Park episode (where you can at least hear Cartman's name). This gets a bit muddled as Terrance and Phillip are "real" actors in the South Park universe with a television show the South Park kids watch, but the characters (one assumes) Terrance and Phillip play have watched South Park. Do what now?
- An episode of The Simpsons has a guest appearance by Richard Dean Anderson playing himself, where his work in Stargate SG-1 is referenced. However in Stargate, Rick's character, Jack O'Neill has openly talked about his love of The Simpsons many times, including comparing Mr Burns to the Goa'uld. The icing on the cake is when Dan Castallaneta, the voice of Homer, make a guest appearance on Stargate... and agrees with Jack's "Burns = Goa'uld" theory.
- The Simpsons has Matt Groening introduced as "the creator of Futurama". Another one has Bart Simpson hallucinating, his classmates appearing as fictional TV characters, one of which is Bender. Finally, a Futurama episode has a pile of Bart Simpson dolls appear as one of the many things in a gigantic (indeed, celestial) ball of garbage.
- One popular fanwank for the Bart Simpson dolls is that it's merch from his stint as the "I Didn't Do It" Boy.
- Also, in the Simpsons episode Mayored to the Mob, Üter wears a Futurama shirt (this episode aired about a month before Futurama's first episode).
- Also, thanks in part to certain former trope-naming episodes of South Park, and innumerable references to each other, South Park, Family Guy, and The Simpsons are all fictional within each other's Universes. But then again, the Griffins have visited Springfield, and Eric Cartman has worked with Bart, so it goes with whatever is funny at the time.
- In one episode of the first season of Lois & Clark, Lex Luthor made a mention about watching Simpsons reruns. In one Simpsons episode, Comic Book Guy saw some problem and said it was a job for, some heroes he mentioned. Then somebody asked about Superman.
- For additional mindwarping, The Simpsons is a cartoon in The Critic - and then Jay Sherman visits the Simpsons family. Gah!
- A rather cute fanwank points out that as a celebrity TV-Critic in The Critic universe, there is nothing unusual about him guest starring as himself in the Simpsons. Had the actual episode replaced Jay Sherman with a guest starring Roger Ebert nothing in the plot would have changed.
- In Danny Phantom, Danny can be see playing a Crash Nebula arcade game. In the Crash Nebula Poorly Disguised Pilot episode of The Fairly OddParents, Crash has a Danny Phantom comic book.
- An episode of American Dad! ended with Peter and Cleveland appearing, but another one had Steve and Roger watch a Family Guy DVD. There's also an episode of Family Guy where Stan and his CIA boss showed up to try and stop Stewie. It gets particularly weird in the American Dad episode "The People vs. Martin Sugar", where Stan explicitly notes Brian as a fictitious character - only for Brian to then appear next to him, ask "do I know you?", then walk off as Stan shouts at him to "stop pretending I don't exist!". This is parodied in the Family Guy episode "Excellence in Broadcasting", when Stan is shown watching the episode and is proud of Brian for becoming a conservative.
- Strangely enough, on an episode of The Cleveland Show where they go to Comic-Con, a giant statue of Stewie as Darth Vader appears in the background.
- A cross-media example: An ad for Team Fortress 2 appeared at the end of The Venture Bros. Season 5 premiere, with some of the mercenaries too distracted by Hank and Dean's antics to notice a Spy sneaking into their base. A little over a season later, Rusty and Sgt. Hatred were seen playing Team Fortress 2 when they were supposed to be working. While characters from both universes have appeared in the interdimensional bar known as The Inventory, they appeared one game apart.
- The Goofy short How to Be a Detective features Goofy reading a Mickey Mouse comic book. You know, his best friend? Then again, most of these kinds of cartoon shorts are anthological and self-contained.
- Dexter's Laboratory had an instance in the Justice Friends short "Things That Go Bonk In The Night". Krunk stays up late watching a multi-day marathon of his favorite show, TV Puppet Pals, finally falling asleep and immediately having a dream wherein he enters the world of the show. The dream predictably goes sour, Krunk wakes up in the midst of shouting, and there's the requisite stinger indicating it wasn't just a dream... and then cut to Puppet Pal Mitch screaming himself awake from a nightmare brought on by having stayed up late watching a multi-day marathon of Justice Friends.
- Tiny Toon Adventures has had a few episodes referencing Batman, most notably the comics and films. Meanwhile, Batman: The Animated Series has an episode where one of the Joker's henchman can clearly be seen reading a Tiny Toons comic book.