There was a skeleton in front of you with a smile on his face. But the atmosphere around him was tense... There is a knife in your hand, a smirk on your lips, a bloodlust in your eyes, and in your head... Question 'how the hell did I get here?', accompanied by a quiet but insistent whisper 'kill, kill, kill' of an spirit who introduced theyself as Chara.

"It's a beautiful day outside. Birds are singing, flowers are blooming..."

This wont end well...

As well as it didn't start so from Sans' point of view. You end up here, in the underground. You started to kill everyone from the very beginning. He was hoping, he was trying to warn you, to convince to rationality for Toriel...

But you didn't listen. You killed them all. You are the one to blame. You are the one who's going to be judged.

Or... Was it someone else entirely?