FNaF.Undertale is a crossover AU between Five Nights at Freddy's, FNaF World, Sister Location and Undertale. The AU is created by Child-of-Sun-Flowers on DeviantART.
The story follows the same idea as Undertale but most of the characters are a mix between their FNaF character and the Undertale character they replace. In this the locations are also replaced with other locations, for example; Waterfall is the Painted Falls and Hotland is Underland.
Here is a list of which Undertale character is replaced with which FNaF character.
- Flowey (The Empty One Role) - Plushie Fredbear from the FNaF 4 minigames.
- Frisk (The Protagonist/Player Character Role) - The FNaF 4 crying child from the minigames, he is named Mark in this AU.
- Toriel (The Caretaker Role) - Spring Bonnie (referred to as a they.)
- Napstablook (The Recluse Role) - Endo-01 (Endoskeleton in the backstage)
- Sans (The Judge Role) - Circus Baby
- Papyrus (The Ambitious Role) - Ballora
- Undyne (The Captain of the Guard Role) - Toy Chica
- Alphys (The Royal Scientist Role) - Mangle
- Mettaton (The Celebrity Role) - Funtime Foxy (referred to as a he.)
- Asgore (The Monarch Role) - Fredbear
- Asriel (The Soulless Angle Role) - Michael (Springtrap (God of hyperdeath))
- Chara (The Fallen Role) - The little girl from Sister Location minigame, she is named Mable in this AU.
- Monster Kid (The Idoliser Role) - Balloon Boy (BB)
- Nice Cream Guy (The Repetitive Vender Role) - Bonnie
- Doggo (The Blind Role) - Foxy
- Temmie (The Village Shop Role) - Plushtrap
- Muffet (The Outrageous Vender Role) - Minireena
- Mad Dummy (The Enraged Role) - Endo-02
- Grillby (The Restaurant Owner Role) - Jack-O-Bonnie
- Bratty and Catty (The Trash Venders Role) - JJ (Bratty) and Chica (Catty)
- Burgerpants (The Oppressed Vender Role) - Freddy Fazbear
- A comic was planned for this AU but it later got cancelled.
- Originally William Afton took the role of Asriel.
- The creator of the AU ships Baby (Sans) and Mangle (Alphys) instead of Toy Chica (Undyne) and Mangle (Alphys), this was also supposed to be shown in the comic.