It is unknown when it will be added, or not at all. Strangely, Update 2 did not feature Nightmare Mangle, despite it being a Halloween character.

Some people wish to have Nightmare Mangle in the game.

Interestingly, they also share the same attack, Unscrew 2.

Nightmare Foxy is also the only nightmare animatronic to show his endoskeleton feet.

Nightmare Foxy is one of two animatronics to have a different set of endoskeleton feet that is used by most other animatronics, the other being Withered Bonnie.

Nightmare Foxy still does not have the long pointy tongue as shown in one of the Five Nights at Freddy's 4 teasers and the title screen of the same game.

It is possible the model for Nightmare Foxy's head was based on Withered Foxy's head.

Oddly, Nightmare Foxy completely lacks fur on his right ear despite having fur on both ears in Five Nights at Freddy's 4.

Nightmare Foxy's loading screen would be referring to that he was still out of order for four games, if the one counted the numeral order of the core games.

This is also true for the other Nightmare animatronics with the exception of Plushtrap, Nightmare, Nightmare Fredbear and the animatronics from Update 2.

Nightmare Foxy having the attack 'Bite 2' is a reference to how he was a suspect of the Bite of '87.

Bite 2 is good to quickly deal damage to most enemies as well as using Hot Cheese 2 that can do huge damage over time. Like Withered Bonnie, he has Unscrew 2 which has a 50% chance to destroy a single target. Nightmare Foxy can be treated like Withered Bonnie. Put 7 globs of hot cheese on the floor, doing massive damage over time to enemies. Like the original Foxy, he lacks animatronic fur from the knee down, revealing three-toed endoskeleton feet. There are two huge cracks underneath his ears, along with a huge hole on both sides of his head. The right ear is ripped from his costume and the left ear has a huge rip. Nightmare Foxy's appearance is almost identical to his core series counterpart, but he is smaller, glossier, and has a shorter snout, which still appears cut almost halfway from the fur.

Nightmare foxy fnaf world