Nightmare (Five Nights at Freddy's)

"I will vomit you back to relieve your horror."

- Nightmare's death quote from Ultimate Custom Night.

Nightmare is one of two main antagonists in Five Nights at Freddy's 4 and is the final boss of said game. He could be seen as the shadow version of Nightmare Fredbear, as while Nightmare Fredbear serves as a nightmarish version of Fredbear in general, Nightmare serves as the specific Fredbear that bit the child's head. He replaces Nightmare Fredbear as the main antagonist on the final night, aptly named "Nightmare" (FNAF 4's 20/20/20/20 mode). He also appears on the cover of Scott Cawthon's book: Five Nights at Freddy's: The Twisted Ones. Nightmare later returns in Ultimate Custom Night.

He is voiced by Eric D. Wald.

Appearance
He is clearly based on Nightmare Fredbear, being some sort of demonic version of the already demonic looking Fredbear. Unlike Fredbear, his skin is translucent, exposing all of his animatronic parts. Upon closer examination, a black mass resides in Nightmare's head.

He is black with a yellow hat and bow tie, the yellow hat having a black trim on it.

Five Nights at Freddy's 4
Just like Fredbear on Night 6, on Night 7 and Night 8, he takes the same role, appearing at 4 AM, and replacing all animatronics, taking up their duties. He must be handled the same way, but Nightmare is more aggressive than Fredbear. Also, he always directly appears at the doorway. Upon being attacked by him, he will appear in a screen similar to Golden Freddy instead of a complete animation. His existence is unexplained, and his purpose is unknown. He is acknowledged in the gallery as a separate entity from Nightmare Fredbear, meaning that he must have some sort of significance.

The Twisted Ones
Nightmare appears on the cover of The Twisted Ones; sequel to The Silver Eyes novel. Despite this, it doesn't appear in the novel at all.

Ultimate Custom Night
Nightmare appears in the Ultimate Custom Night update alongside his fellow nightmare animatronics. He is invisible to the player and approaches the right door, with only his eyes indicating his presence. The player must close the right door to send Nightmare back into the darkness.

Trivia

 * He is similar to Shadow Freddy in several ways leading to some theories of them being the same entity.
 * A folder in the game files suggests that Nightmare may, in fact, be the Shadow Freddy that has been appearing since Five Nights at Freddy's 2.
 * This, in turn, can confirm that Nightmare is a shadowy version or form of Nightmare Fredbear, just as how Shadow Freddy is the shadowy equivalent or form of Golden Freddy/Fredbear, thanks to their similar models and even posture.
 * He is assumed to be a personification of Death, meaning that the Fredbear-type appearance is only a simplified form and that his true form is incomprehensible. His quotes in the Ultimate Custom Night supports this.
 * His current role in the story is unknown.
 * Somes believe he's just the incarnation of the Kid's Nightmare and so, the final obstacle for the kid to finally die.
 * Nightmare is the only one animatronic who doesn't have a jumpscare in the Extras Menu.
 * Nightmare is the only animatronic in the fourth game who doesn't have an animated jumpscare similar to Golden Freddy from the first game.
 * Upon close inspection, Nightmare has transparent parts in is body, this could imply that he is a ghost.
 * An opinion gives that his black appearance makes him a spirit.
 * However, in Ultimate Custom Night, Nightmare is not transparent.
 * His claws, teeth and black color make him similar to Venom.
 * His jumpscare message sounds like a ambulance.