This is where a work is adapted, then the adaptation is adapted, and so forth. The adaptations pile on a ridiculous number of times, usually resulting in the actual source material appearing completely unrelated.
This is often done to capitalize on a popular franchise, especially when an expired copyright is involved...
It's important to note that this is not necessarily a bad thing, as the adapted works sometimes end up being genuinely good, or at least lucrative.
- The Addams Family: Newspaper Comic —> TV show —> Cartoon —> Video Game —> Movie —> TV show loosely based on movie —> Video Game —> Sequel to movie —> Broadway Musical
- 300: Actual events —> unreliable historical document by a man who was taking a break from writing about giant ants —> Movie —> Graphic Novel —> Movie —> Video Game —> Sequel to second Movie
- Gods and Generals: Actual Events —> Book —> Movie —> Video Game
- Mahou Sensei Negima! Manga —> alternative retelling OVA —> alternative retelling anime —> alternative retelling Manga (which outlasted the anime its based on).
- The Hitchhiker's Guide to the Galaxy: Radio Serial —> Books —> TV Series —> Adventure Game —> Movie
- Teenage Mutant Ninja Turtles: Comic —> Cartoon —> Comic based on cartoon —> Movie —> Band —> ...
- The Marx Brothers' Animal Crackers: play —> what the Marxes did to the play —> movie —> play based on the movie
- Dracula and Frankenstein, as well as their characters.
- Uncle Tom's Cabin: pre-civil war book about the hardships and immorality of slavery —> straight play adaptation —> Jim Crowe era minstrel show about the perks of being subservient to white people —> movie adaptation. Guess which one is best remembered.
- Freaky Friday: Children's novel —> Movie (1976) —> Movie (1995) —> Movie (2003).
- Also: Children's novel —> Sequel —> TV show
- Transformers: Toys —> Comic —> Cartoon —> Animated movie —> Sequel cartoons —> Reboot cartoons —> Lots lots more comics —> Live-action movie —> Another reboot cartoon —> Even more comics, and prose —> Second movie —> Video game —> More prose —> Slightly video game/movie-based reboot cartoon —> Third Movie —> Spin-off to the previous cartoon —> Fourth Movie. Whew.
- The Legend of Zelda: Video games —> Cartoon —> Comic
- Little Shop of Horrors: Movie —> Stage musical —> Movie of musical —> (Extremely) short-lived Saturday morning cartoon show
- The Mighty Ducks : Movie -> Actual hockey team -> Cartoon
- BIONICLE: Toys —> Comics —> Web games —> Novels —> Non-canon video game —> Direct-to-Video movies —> Novels based on those movies —> Another non-canon video game —> Novels —> Another DTV movie —> Web serials —> Web novel.
- The entire The Mummy franchise: 1932 Movie —> 1959 Remake —> 1999 Reboot —> Sequel —> Video Game —> Prequel Spin-Off —> Video Game —> Prequel to spin-off —> Sequel to Reboot sequel —> Sequel to original spin-off —> 2017 Reboot
- The Hair Bear Bunch was an unlicensed Animated Adaptation of the sitcom Hogan's Heroes, which was an unlicensed adaptation of the film Stalag17, which was adapted from the Broadway play of the same name, which was based on real experiences in a prisoner-of-war camp in Austria. It was a steady slide from reality, to talking bears with funky hair.
- 101 Dalmatians: Children's novel —> Animated film —> Second children's novel —> Live-action film —> Television series —> Second live-action movie —> Non-canon video game —> Direct-to-Video sequel of animated movie
- Sailor Moon: Manga —> Better known sequel —> Anime —> Musicals —> Non-canon video game —> Live-action television series —> Another anime —> Second Set of Musicals
- Les Misérables: Novel —> Musical —> Film. This one is interesting, as multiple movies have been made of the book, but only in 2012 did they actually make a movie of the musical
- Rambo: Novel —> Film —> Sequels to the film —> Novelisations of the sequels, written by the author of the original novel
- The Strange Case of Dr. Jekyll and Mr. Hyde: Novel —> Play —> Many films based on the play
- The Producers: Movie about a musical —> Musical —> Movie adaptation of the musical
- RoboCop: 1987 film —> 1988 animated adaptation —> Two film sequels —> Comic sequels —> Futuristic comic crossover —> 1994 television series based off the first two films only —> 1998 animated series (with no ties to the first) —> 2000 miniseries based on the first film only —> Film reboot
- The King and I: Anna Leonowens's memoirs —> Anna and the King of Siam (novel) —> Broadway musical —> Live-action film —> Animated children's film