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 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 tears (mistaken for acid rain) 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. Naps Napstablook's home, seen on the left in this picture, is located to the east of Napstablook's snail farm. 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 does 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 typing quirks - missing capitalization, abundance of ellipses and the frequent use of 'oh' - and the way Mettaton says "NO, WAIT BL–" suggesting that he was referring to Napstablook as "Blooky," Napstablook's nickname.
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.
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.