Believe me, I was the same. I am pretty sure I looked like a stoplight married a fish out of water.
Are you talking about the Edge/Papyrus comic where Pap is being a badass?
Honestly I think Papyrus is just so naturally good at subterfuge--he proves it more than once in the game, and it's obvious his personality is mostly a facade. If you look at all the other Papyri from the other universes, it becomes more likely, because it doesn't seem like a Pap at his core is a pure cinnamon roll, because the only ones remotely like that are him and Sugar--and Sugar literally had submission beaten into him, so that explains him.
That isn't to say he isn't a good person, he's just not nearly as harmless as he appears to be, and he wouldn't take kindly to someone like Edge coming in and fucking up everything.
Who's playin'? Mutt IS the librarian...