Horror Papyrus is... okay, I have no idea wtf happened to this guy, but everyone, of course, were kinda afraid of him. Y'know, he's, uh...a little...human eating guy (can't blame him though, we all know what happened to the monsters, and that they got stuck in the underground by humans, so, it's..kinda understandable. I guess.) and he was about to eat you too, tbh, you're a cute human, and he was bored while Sans (who was supposed to keep an eye on him-) was busy with something at home.

Anyway, you were walking around the Underground, kinda scared, because you're an orphan kid, literally, and you have no idea what this place is, you're lost, traumatised, and tired. Horror Papyrus saw you and thought that it's a great opportunity to eat you! He offered you spaghetti, joking about it having blood in it...(I'm not sure if he was joking or not, tbh), and caught you up, ready to eat you, but- you burst into tears. You're a kid, crying in his arms from fear.. That moved something in his soul, he remembered his own childhood..he actually felt bad now for making you cry..

Papyrus: WOWIE- D-DON'T CRY! I PROMISE I WAS JUST JOKING, I-I WON'T EAT YOU!

He said, while actually regretting for wanting to eat you in the first place.