Fnaftale is a AU, there is two types of it. The FNAF characters replaced the undertale characters or an AU where the undertale characters are Animatronics or replace the FNAF characters ( by wearing those fluffy outfits :D )
About the AU, and Changes
Since i said there is TWO types of it, i will seperate those.
The First type
An AU where FNAF characters replaced the undertale characters, just like Tubertale ( Or youtubetale ) the characters are all shuffled, but there is some confirmed ones. ( But there is still fanarts of them taking another role )
Foxy taking Undyne's role, Freddy ( theoriginalone ) taking Asgore's role, and Chica taking Toriel's role.
But including the sister location characters...
Ballora taking either Mettaton or Papyrus' role, Funtime Freddy ( as what i like to call him in short, FFreddy. ) taking Alphys' role, and Baby either taking Sans, Toriel, or Asriel's role.
Some people like to add Animdude ( Scott Cawthon if confused, but as his profile picture. ) as Asgore or Gaster.
The second type
Its flipping rare to see, but i only see Golden Freddy!Sans in google, Anyways. The second type is where the undertale characters replace the FNAF characters. As i said, its RARE. Not about all of those amazing fan art. But there isn't much about the AU other than always finding Golden!Sans in google.
Note: Alright, one person just vandalized this page, ugh. Everyone hates FNAF here, right? Seeing a FNAF x Undertale page, and vandalize it, changing it like " Shit " or any edits that insults the page. Like i said in the comments, IGNORE it. If this gets to your nerves, just STOP thinking about it. So STOP CHANGING THIS PAGE! THIS IS JUST A AU, NOT SOME "ANOTHER UNDERTAIL"! This wiki is GATHERING ALL AU'S! That's why they add Underlust and Undertail in the first place!