Is there a joke I'm missing in the third panel because from what I can infer, Clownpiece just took a sh*t on Hecatia's head?
She might have procured it from elsewhere, but regardless, the joke is that Hecatia's hair color reacted to it. (Also, children/childish characters elsewhere in manga are sometimes known to have a child's obsession with poop, if that's your question.)