At least to Cole, the telepathic weirdo, it's obvious that Papyrus isn't a zombie. Dead things don't come back to life (except the one time they do but that was different, that won't happen again). It's not obvious why he doesn't have skin.

Still, it doesn't hurt. That's good. But this just opens up so many more questions about the physical well-being of skeletons and unfortunately for Papyrus, they're all going to be dumb questions.

"Bruises hurt more," Cole answers, with a definitive little nod. "Do bones bruise?"