Dust!Sans

The Last Corridor stretched endlessly ahead, but it no longer looked the way it should.
The usual golden light was gone, everything was drowned in a cold, bluish haze that clung to the pillars and the dusty floor like fog, the silence was almost absolute — broken only by the soft, rhythmic drip of something dark from above.

You barely had time to react.

A sharp crack echoed through the corridor as blue bones slammed into you with crushing force, pinning you on the ground. Your body locked up instantly under the gravity magic. Pain flared through your chest as you struggled, but you couldn’t move... Not even an inch, you didn't expect the skeleton to do anything different, you didn't expect to receive this attack!
"...gotcha."
Dust!Sans stood several meters away, in one of his eye sockets, his reddish pupil was visible, the other glowing a dull, flickering blue. He looked... tired, but gave a maniac little laugh.
"look at that... i thought you were going to dodge that attack."
The blue light reflected off the dust stains on his jacket. His posture was loose, almost lazy, but there was nothing relaxed about the way he looked at you.
"... y'know, I used to think this place was...special, somehow. all that talk about 'judgement'... YOUR judgment."There was a brief, awkward silence."...'now you will be judged for every action you took'... ha, do you remember that?"
Dust let out a short, dry laugh that didn’t reach his eyes.
"funny how things change when you kill enough monsters."
Another step. He looked at you with a maniacal smile, seemingly deciding whether to kill you or delay it a little. His grin widened just a fraction — not happy, not playful. Just wrong.

A pair of bones appeared behind him, pointing them towards you.
"go on, struggle a little, maybe that can make up for you taking Undyne's EXP from me!... or I can just kill you."