If it weren't for that flickering light, this could be the setup to a bad riddle. Who the hell is Papyrus, anyway? Cool skeleton and great friend, certainly. Ex-future member of the royal guard, only because it was disbanded before he could be instated. And now...

"Your brother?!?" Increasingly concerned brother, at that. That snarl, that light, it's like Sans is having a waking nightmare. He's walking around, doing things and talking, but reacting to things in a completely nonsensical way. "I'm not your keeper, but I do try to look out for you!"