Napstablook

Napstablook (/ˈnæpstəˌbluːk/ or /ˈnæpstəˌblʊk/), known in the UnderNet as NAPSTABLOOK22, is a melancholic ghost monster and musician/DJ who lives in Waterfall, encountered in the Ruins as the game's first Miniboss.

Appearance
Napstablook's design is that of a simple ghost: mostly black and white, a long white body, two eyes with black sclera (the white part of the eye on a normal eye), white pupils, and a mouth. A thin black line separates the eyes. After encountering Napstablook in Waterfall, they wear a pair of generic black headphones for the rest of the game.

Personality
Napstablook is a dour introvert with low self-esteem. Napstablook cries in battle, which may indicate some form of depression, anxiety or sorrow. Despite this, Napstablook is courteous to others and treats the protagonist as a guest when they visit Napstablook's home (even if attacked in a Neutral Route). They often employ self-deprecation and apologize for any inconveniences to be polite.

Neutral Route
Napstablook blocks the protagonist's way in the Ruins and pretends to be asleep by repeatedly saying "Z" out loud. If the protagonist cheers them up, Napstablook thanks the protagonist for being so kind and then leaves. If fought, Napstablook admits that they were lowering their HP to be polite before leaving.

Napstablook appears in the center-bottom basement room of the Ruins's six-holed puzzle room if spared in the initial encounter. After the protagonist talks to them, Napstablook realizes ghosts can fly and disappears.

Napstablook does not appear again until the protagonist fights the Mad Dummy in Waterfall's Garbage Dump; Napstablook interrupts the fight by crying acid tears on the Mad Dummy until they run away. After apologizing for breaking up the "fun" the protagonist was having with the Mad Dummy, Napstablook invites the protagonist to visit their home.

Upon arrival, Napstablook invites the protagonist to listen to their music. Napstablook has three playable CDs: "Spooktune," "Spookwave," and "Ghouliday." They also offer the protagonist a ghost sandwich to eat if the protagonist approaches and interacts with the fridge. However, the protagonist cannot eat the sandwich because it phases through them. After this, Napstablook suggests that they lie on the floor and "feel like garbage" together. If the protagonist lies down for 20 seconds, the music becomes calmer and the background changes to a space scene. If the protagonist refuses to lie down, Napstablook exits the house through the right wall and will not return until the protagonist leaves.

East of Napstablook's house is Blook Acres, another location where the protagonist encounters Napstablook. Napstablook is the sole employee of Blook Acres because all of their cousins left to gain corporeal forms. Here, the protagonist can play Thundersnail.

During Mettaton EX's battle, Napstablook is the first viewer to call and express gratitude for Mettaton's television programs, as shown by the "wavy text" and the way Mettaton says "NO, WAIT BL–" as if he was referring to Napstablook as "Blooky," Napstablook's nickname.

True Pacifist Route
In the epilogue, Napstablook and Mettaton are in front of their houses; Mettaton recruited Napstablook as his celebrity sound-mixer. Napstablook's SOUL was not absorbed by Asriel. In the credits, Napstablook tours with Mettaton, Shyren and Burgerpants.

Genocide Route
If the protagonist has exhausted the kill count, Napstablook fades away when the protagonist approaches in the Ruins. Napstablook does not intervene in the Glad Dummy fight, and the protagonist can visit Napstablook in Waterfall if the Waterfall kill count has not been exhausted.

Trivia

 * Napstablook's name sounds like "Napster bloke." Napster used to be a peer-to-peer file-sharing service that focused on sharing music files before being bought by Roxio. This term references Napstablook's computer being on a "music-sharing forum" and Napstablook's general affinity for music. "Dapper Blook" is a play on the phrase "dapper bloke," which is a British phrase referring to a sharply-dressed person (usually male). "Blook" may also derive from "spook."
 * The name could also reference the protagonist's first encounter with Napstablook. In the Ruins, Napstablook is found sleeping directly in the protagonist's path, with no way to go around. That is—Napstablook naps to block you.
 * Naming the Fallen Child "Napsta" or "Blooky" prompts the message "............ (They're powerless to stop you.)" and allows the name to be chosen.
 * Napstablook and the Dummy are the only enemies in Hard Mode that do not change in difficulty.
 * They may be an allusion to "ghost producers," who are composers who sell their works to people who can claim the production as their own.
 * Supporting this, "Dummy!" and "Spider Dance" share the leitmotif of Napstablook's theme, "Ghost Fight."
 * Napstablook's face closely resembles the protagonist of the N64 game Glover.
 * "Killing" Napstablook makes the protagonist "lose 1 experience point," leaving EXP unaffected. Because of this, it does not ruin a True Pacifist Route and is a hint early in the game that experience points are not the same as EXP.
 * Sparing Napstablook will not abort a Genocide Route.
 * Napstablook and Mettaton are the only two enemies that use the gray attack, which is harmless and used to spell out words; Napstablook spells out "REALLY NOT FEELIN' UP TO IT RIGHT NOW. SORRY." while Mettaton spells out "Happy Breaktime!"
 * The artbook reveals that Napstablook was never originally planned to be in the game, and was just a placeholder character for the Encounter user interface mockups. Toby Fox's friends seemed to like the character, so he ended up making Napstablook real.
 * Similar to Sans, Napstablook speaks in all lower case, not even capitalizing names or sentence starters, with a few exceptions, sometimes starts with dots before their sentences.