A conversation about Halloween

This conversation took place between Rui and Ben last night.

Rui : " I want to be dressed up as a fairy. I want to make a magic wand."
Ben : "Ok. Let's make one now."
Rui : "Yan will also be a fairy. I want to make a wand for her too"
Ben : "OK."
Rui : " What will Mummy be dressed up as?"
Ben : "(stammering) err... she will just be mummy. That's scary enough."

Our helper Yayu overheard and burst out laughing. I laughed too, despite myself.

Duh...