Nubert's movin' up in the world.
Nubert serves as a running gag, in that everybody loves him for no apparent reason.
Nubert is a red bump-like Darkner without any limbs. He sports a wide smile and two small eyes at the very top of his body. When talking he moves his body from left to right.
Nubert often talks in third person. He likes to mention that everybody loves him, which is reflected in Mousemillian and Queen's opinions of him. Nubert is very generous, as shown when he gives Kris his Fiber Scarf and at the end of Chapter 2 when he declares he will give his riches to the weak.
Nubert is also shown to be incredibly selfless, as he refuses to leave Cyber World unless every enemy was recruited.
In the Cyber Field, Nubert appears behind a puzzle where Kris has to type "APPLE." After solving the puzzle, Kris can find Nubert and a chest containing a Fiber Scarf. Nubert congratulates Kris on getting past his forcefield (despite him not knowing how the forcefield got there) and says that he is giving Kris his treasure (despite not knowing what is inside). If the party backtracks here using the Warp Door, Nubert is no longer present; the digital billboard featuring Nubert now depicts him wearing a wig, and if interacted with it mentions that Nubert is moving up in the world.
In the Trash Zone, Nubert appears next to Trashy and the eggplant that looks like a trashbag. If Kris talks to Trashy immediately after Ralsei heals Susie, Susie criticizes Trashy for spoiling the emotional moment before she and Ralsei notice Nubert and express excitement. Nubert mentions that everybody loves him, which is why he lives in the trash. If the party backtracks to the Trash Zone with Noelle, Nubert comments that he likes the name "Nuelle." During the Snowgrave Route, Nubert stops appearing once Noelle gains the Frostmancer title, but reappears as normal if the route is aborted. If the party backtracks here using the Warp Door, Nubert is no longer present.
In the Queen's Mansion, Nubert can be found at the 2F Dinner Party Section A, wearing a blond wig and dining with Mousemillian (a Maus wearing a blond wig). When interacted with, he mentions that he is moving up in the world. Mousemillian claims to be leagues and inches above other mice, but still behind Nubert.
Nubert only comes to Castle Town if the party recruited all possible enemies in Cyber World. If only some enemies were recruited, Queen comments about Nubert's absence, to which Trashy interjects that Nubert said he would only come if everyone else did.
If Nubert comes to Castle Town, he can be found hanging out with the Little Ball, to whom he has given his blond wig, in an act Nubert describes as giving his "riches to the weak."
- During Undertale's sixth anniversary stream, Nubert was present in the altered version of Chapter 1 played by the streamers. He appears twice, first next to the Bake Sale in the Forest, and then among the celebrants atop Card Castle after defeating King, standing next to Mr. Elegance. When interacted with, he introduces himself and says that everybody loves him, to which either Ralsei or Susie responds "My man!"
- He is known as ポイン [Poin] in the Japanese localization.
- Nubert is likely based on a pointing stick, which is often colloquially referred to as a "nub."