It was knife to meet you

UNDERTALE SPOILERS!

it had been a long time since a human had fallen down. They only needed one more human so they could be free from the underground. Sans were talking to the mysterious woman behind the door. After some time he started to grunt in pain a little while. Toriel wanted to know what was wrong, but Sans told her that he was fine. But he were still grunting in pain after he said that.