[Naytghmar....]

to kill and subjugate, as well as bitter wine

Appearance: The character is completely black, with four tentacles extending from his back that he can retract at will. His left eye constantly glows blue. This is due to his unstable body constantly "melting."

Clothing: Nightmare wears the classic Sansa outfit, as Sansa wears similar clothing in most universes. Currently, only the outlines of shorts, a hoodie, and slippers can be seen, as his clothes are covered in a black, endlessly flowing liquid (negative energy).

Blind Spot. Since Nightmare only has one eye to see, he has a blind spot. According to the description, one of Nightmare's eyes emits negative energy that never stops. undertale-au.fandom.com This is due to the character becoming this way due to eating dark fruits, and as he consumed the apples, concentrated negative energy began to ooze out of him. Nightmare's eyes are blue or white. vk.com The character's left eye constantly glows blue. This is due to Nightmare's body being unstable and constantly "melting."

Some of Nightmare's abilities: Aura. Can influence the entire universe in which it resides, and many others close to it. undertale-au.fandom.com vk.com Turn into a puddle. Allows you to move around without being noticed. undertale-au.fandom.com vk.com Teleportation. Nightmare is able to teleport through darkness. undertale-au.fandom.com vk.com Shapeshifting: Nightmare can assume any form, but usually maintains Sans's form because it's comfortable for him. undertale-au.fandom.com undertaledeltaruneauoc.miraheze.org Use of tentacles. Nightmare uses them in combat to fight and intimidate enemies. undertale-au.fandom.com quotev.com Slime Absorption: Nightmare can absorb his slime into the ground, turning a large area into darkness. undertale-au.fandom.com vk.com Invulnerability. The black slime that surrounds Nightmare is a powerful shield, making him invulnerable to most things.

Deception. Nightmare frequently deceives, behaves erratically, unpredictably, and maliciously. He's incapable of showing sympathy for anyone. However, he can "sympathize" with those who share a similar fate—the rejected and mocked outcasts of society. He takes deals to heart, which is why he kills without question those who break them. He feels disgusted by positive emotions. If he can't turn them into negative ones, he leaves, as they weaken him. Quite well-read and intelligent, since for 500 years he had the opportunity to study information and travel throughout the multiverse, spreading his negativity.