Folgers Crossover

We've secretly replaced Akane Tendo from Ranma ½ with Akane Kasuga from Kimagure Orange Road. Let's see who notices.

A Folgers Crossover is one of the more unusual means by which a Fan Fiction author can choose to implement a Crossover—rather than have the casts of two different shows meet, just swap a character from one with a character from the other and let hilarity ensue. It can be a physical transposition, or a purely mental exchange—and for extra bonus fun and maximum initial confusion, have the characters share the same first name. Or ~~worse~~ better, be the same character from two different continuities.

The result is often a Trapped in Another World story, in which both casts may find themselves working to return the visitor to their own world/timeline/universe and get their missing compatriot back. Meanwhile, the experience may provide enlightening insights for the displaced characters, not only into themeselves and their relationships with the rest of the cast, but also into the personalities and histories of the people they know.

Very often played for laughs when the characters involved have radically different personalities.

The trope name comes from an advertising campaign for Folgers instant coffee from the 1970s and 1980s which took the viewer inside various gourmet restaurants while a voice-over whispered, "We are here at (name of four-star restaurant), where we've secretly replaced the fine coffee they usually serve with Folgers Crystals. Let's see if anyone can tell the difference!"

Sub-Trope of Fusion Fic. Often, but not always, a subtrope of Intercontinuity Crossover or Trapped in Another World

Compare Transplanted Character Fic and Freaky Friday Flip.

Not to be confused with a Doppelganger Crossover.

Examples of Folgers Crossover include:

Fan Works

The page quote refers to an actual fic entitled A.K.A. Akane-Chan?, written in 1993 by Jeff Yang, which may be the Ur Example of the trope. In it, Akane Kasuga and Akane Tendo swap minds (and worlds), and the lesbian Kasuga gets a crush on female!Ranma, without knowing anything about his intergender condition.
Gregg Landsman's Nobody Dies includes an extended sequence where the canon versions of Asuka and Shinji change places for several chapters with their counterparts from the world of the fanfic.
Played with in Mithril Moth's Fire in the Water, a Ranma ½/Magic Knight Rayearth crossover in which Ranma's girl form is the body of Hikaru Shidou, who drowned at Jusenkyou a thousand years earlier thanks to Time Travel shenanigans—and Hikaru's spirit begins possessing Ranma's body.
In the Hands of a Real Hero by A. Amishi tells the (incomplete) story of what happens when a freak accident exchanges Kazuki Yotsuga and Zinv (from Dual! Parallel Trouble Adventure) with Shinji Ikari and Evangelion Unit 01 (from Neon Genesis Evangelion).
Another Evangelion example -- Castling by Andew J. Talon explores what happens when canon Shinji trades places with a confident, well-adjusted Shinji from another timeline while fighting Leliel.
The Ranma ½ fic Goddess of My Harmful Deeds by Richard Lawson offers a chance for both recovery and redemption to the Akane of the infamous The Bitter End by James "Zen" Bateman via the device of a brief exchange of minds between her and the Akane native to Lawson's Thy Inward Love series.
Towards the end of the epic Ranma ½-centric Mega Crossover A Tale of Two Wallets by Jim Bader, Peorth arranges a timeline comparison between the Alternate Universe of the story (in which Nabiki is happily engaged to both Ranma and Shampoo) and a scratch copy of the canon Ranma ½ timeline, to fine-tune the destiny of the former. Unfortunately, their Nabikis get swapped in the process, leaving the canon moneygrubber in a universe where her counterpart has given such behavior up and has two devoted lovers (among many other changes), and said counterpart finds herself in a universe where Ranma distrusts her (and Shampoo), and is engaged to Akane.
In Dogbertcarroll's Lex Marks The Spot, a DC Comics/Buffy the Vampire Slayer crossover, Xander Harris and Lex Luther get mindswitched into each other's body, across universes. Xander decides to use Lex's resources to do good while acting like an eccentric supervillain, just to troll the Justice League. Meanwhile, Luthor is consuming everything he can find about Superman and discovering just how close to Stupid Evil he's been for years.

Web Original

Offering up an improbable crossover in the style of the Folgers commercial quoted above is something of a running game in the various "Crossovers That Should Not Be" threads at the Drunkard's Walk Forums "Other People's Fanfiction" board. Some examples:

We've secretly replaced Charlie and the Chocolate Factory's Mike Teavee with ReBoot's Mike the TV. Did anyone notice?
We've replaced Bella Swan with Bellatrix leStrange. Let's see who doesn't notice.
We've replaced Bella Swan with Elizabeth Swann. Hijinks ensue, and all the rum is gone for some reason.
We've replaced Moose from Archie with Mousse from Ranma ½ -- let's see how much property damage ensues!
We've secretly replaced Prince Zuko of the Fire Kingdom with Danny Zuko of Rydell High School. Let's see how long it takes Katara to get into tight black leather pants.
We've secretly replaced Mugi from K-On! with Mughi from Dirty Pair...
We've secretly replaced Spike from Cowboy Bebop with Spike from Buffy the Vampire Slayer, who we've replaced with Spike from My Little Pony: Friendship Is Magic, who we've replaced with Spike from Transformers, who we've replaced with Spike from Degrassi Junior High, and so on...

Multimedia

Whip and Wing, in which Indiana Jones and Daring Do swap universes.