No Inner Fourth Wall

When No Fourth Wall and Show Within a Show love each other very much... ahem. Sometimes you have a Show Within a Show. In those cases you have a fictional universe within a fictional universe. No Inner Fourth Wall happens when there's no fourth wall between those, but the fourth wall remains between the viewers and the main fictional universe.

Often used in Rage Against the Author or Interactive Narrator scenarios, where the "real world" author is also fictional.

Examples of No Inner Fourth Wall include:

Comic Books

Lampshaded in Animal Man. At the Denouement of the metafictional madness, the protagonist meets his author, Grant Morrison. The Grant Morrison in the comic mentions he's not the actual Grant Morrison, but a fictional representation of Grant Morrison.

Fan Works

In the final chapter of Drunkard's Walk II, Quincy (from the anime Bubblegum Crisis) tells peripatetic metahuman Doug Sangnoir that he's a roleplaying character Quincy created as a young man, Sangnoir angrily retorts, "I'm no more fictional than you are."

Film

In Last Action Hero, Jack Slater finds out he's a movie character from his fan, Danny. Danny never finds out that he's a character from Last Action Hero.

Literature

Jasper Fforde's Thursday Next, with its mind-bending use of metafiction, plays with this. Thursday enters fictional worlds but hasn't yet found a copy of The Eyre Affair - at least until the fifth book, when she does, and this trope is demolished.
- In the sixth book, the protagonist is the fictional Thursday who plays the role in the books published in the "real" Thursday's world. At one point she thinks that even when she's not being read, she can't help feeling that someone is controlling her actions and reading her mind.

Video Games

Eat Lead: The Return of Matt Hazard has this, there's no fourth wall between the 'real world' and the video game world, with the video game characters being interviewed for biographical documentaries, but there is a fourth wall between the world QA and Wellesly inhabit and ours.
In The Empty City, one of the characters experiences all the characters from the television coming out of it into the 'real' world. They go away when he turns it off.
Star Ocean: Till the End of Time. The characters eventually find out that they're characters in a video game. Then they break out of it. Of course, they break out into ANOTHER world, and are still in our video game... so effectively, the original part was a videogame INSIDE a video game!
Viewtiful Joe is fully aware of all the Toku film tropes he encounters, but never notices any non-overlapping video game cliches.
In Morrigan's ending in Tatsunoko vs. Capcom: Ultimate All-Stars, she takes advantage of Yami's warping of dimensions to escape the game itself and enter the real world, only to be repeatedly schooled by the kid playing the game. Who is definitely not the person who just got the ending. Curses.

Web Original

The Homestar Runner universe is full of shows within the show and sub-universes, most of them created by Strong Bad. They all interact with the main universe from time to time, which has No Fourth Wall in the first place.
- 8-Bit Is Enough is perhaps the best example, which finds Strong Bad hopping in and out of a variety of in-universe video games.
The Church of Blow's plot follows Cornelius Blow who, towards the end of the story, discovers he is a fictional character and has a conversation with his "actor" who is also fictional. Unlike many examples, this is played for drama as Cornelius comes to terms with his fictionality.

Web Comics

The characters in Kid Radd are aware they are in a video game, and at one point talk to a 'player', but only very rarely do they show awareness of being in a webcomic.
The Protagonist of Erfworld is aware he's in some kind of tabletop military gaming simulation-like world, but no one has any idea they're in a Webcomic. Except possibly Charlie.

Western Animation

Duck Amuck, when it turns out the artist is Bugs Bunny.
- And the Spiritual Sequel, Rabbit Rampage, drawn by Elmer Fudd.
One of The Simpsons "Treehouse of Horror" episodes involved a remote control which brought television to life.
Likewise, one Family Guy Halloween special involved Stewie getting Trapped in TV Land.
The entire premise of Captain N is that a boy from the "real world" finds himself in "Videoland". However, said "boy" from the "real world" is also fictional from our point of view.