Well, I tries to beat Sans again (because my sister wanted us to wait on resetting) and I did it. :3
But he called me a freak. :(

Anyways, my friend Mell was at the same time starting another play through. She got to Toriel, and this happened.

Sooooo...... Yeah?....

I looked it up later, and of all the people who can't kill you, it's Papyrus. When he deals what normal enemies would kill with, it just takes you to the garage.

OF ALL THE ENEMIES, IT'S PAPY THAT IS INCAPABLE OF KILLING YOU.

That is very discomforting.