Undertale: Judgement Day (Roblox) Wiki

The tree spirit created Nightmare to protect the side for negative feelings. With his brother (Dream) they served as the tree's guardians. As a child, Nightmare cared about his brother and the tree that gave them life. But one day a village had formed near the tree. Dream befriended villagers whilst Nightmare is beaten and bullied by them for being the guardian of the negative side of the tree. He is seen trying to take care of his brother's apples. Later on, as the bullying gets more intense, he thinks his apples are not good enough and are looked down upon. His brother reassured him that his fruit is just as good as him

People traveled from far and wide to get just one golden fruit from his brother. Nightmare envied his brother because no one would take fruit from his side of the tree. One day, he took an apple from his brother's side, to show he could take care of it. But a being who is filled with negative feelings will turn a positive apple into a negative one. When trying to take care of one of Dream's apples it turns black like Nightmare's fruit. Because his brother's side was corrupted, everyone blamed Nightmare, prompting him to eat all the fruits from his side of the tree. It resulted in him growing tentacles and coughing up black goop. He began to hate Dream and want to kill him. At this point, Nightmare became the character we know of now. Some may think that Dream is, in some way, responsible for whatever happened to Nightmare. (Source: https://undertale-au-fanon.fandom.com/wiki/Sans/Dreamtale/Nightmare!Sans#:~:text=Origin,tree%20that%20gave%20them%20life.)

Music: Black Apple

Attacks Information Cool Down Special Effects
Nightmare A black circle expands and freezes anybody caught in it. After some time it comes back in 60 Seconds Colours change for anybody caught in attack
Tentacle Stab A black tentacle shifts across the floor 5 Seconds None
Tentacle Slam A tentacle slams down on the ground creating a blue explosion wherever the Sans clicked 2 Seconds KR
Void A circle slowly starts spreading until it has a long range. After some time, it comes back to the Sans 20 Seconds Slows people down if caught in circle
Goop Spikes Dark spikes appear wherever the Sans is facing 7 Seconds Slows people down if hit by a spike


  • Use Nightmare and then use attacks on whoever goes through it
  • Remember that Nightmare! Sans has the highest BASE(NO HEALS) HP in the game normally achievable. As such, do not worry too much about self-preservation unless you going up against a strong-hitting combo or are at low HP.
  • Always target whoever has the Star Staff, as it has extremely high damage and is designed to counter your attacks.