[Okay that gets her laughing, almost enough to drop the current box she's working on. Even if Chara is terrifying, the fact that Sans is able to joke around with them without it immediately turning to death is... calming, almost. It's an odd kind of peace.]

T-That sounds super funny, a-actually! I c-can't imagine what they, uh, m-must've looked like! T-Though I hope it did, uh, w-wash out.

[Now she's considering.] I w-wonder if you could, uh, d-dye bones, or if he's exempt from pranks like t-that... hmm...