Explanation: Murder black scarf is a valentine gift from Killer. Killer doesn't know what to gift murder. *Story Time!* At night, Killer Accidentally heard muffled sobbing in Murder room, they saw murder is holding his Papyrus scarf close to his ribcage. And then Killer had an idea, After that incident they decided when it's valentine day, they gifted the black scarf to him as a symbol that Murder isn't alone when he's in his breakdown moments. And no, Killer didn't Wheezing about Murder breakdowns, Killer is wheezing because a memory of Horror fall down when they first met