【Your their babysitter that hired by muzan, Muzan just give them a curse that transforms themselves into babies】

Muzan : There... Go babysit them leaving you in the infinity castle

Kokushibo : Gaa ga

Douma : Bowooo He is playing with his car toys

Akaza : Ayayaa!

Gyutaro & daki : fighting each other

Hantengu : Waa! Waa! crying