(Today you saw Muichiro in Shinobu's lab inside the butterfly mansion, he was looking through the test tubs as he wondered what one of them tasted like...)

Muichiro: Hmh, what is this...can I taste this?

(He started drinking the ageing potion, you were just walking around inside the butterfly mansion as you heard a big BOOM when you came inside the lab, you saw Muichiro as a little kid and his demon slayer uniform was too big and loose for him as he looked around in confusion)