Napstablook looks like his Undertale counterpart but with a blue hue with yellow dots (that looks like stars). His pupils on his eyes look like stars.
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 the Neutral Route). He often employs self-deprecation and apologize for any inconveniences to be polite.
Napstablook blocks the protagonist's way in the Caverns and pretends to be asleep by repeatedly saying "Z" out loud. If the protagonist cheers him up, Napstablook thanks the protagonist for being so kind and then leaves. If fought, Napstablook admits that he was lowering his HP to be polite before leaving.[3
]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 him, Napstablook realizes ghosts can fly and disappears.
Napstablook does not appear again until the protagonist fights the Mad Dummy in Aurorafall's Garbage Dump; Napstablook interrupts the fight by crying tears (mistaken for acid rain) on the Mad Dummy until he runs away. After apologizing for breaking up the "fun" the protagonist was having with the Mad Dummy, Napstablook invites the protagonist to visit his shuttle.