Blue & Pink Monsters

My family has this tradition of playing "monster." When my dad would come home from work he would chase me and my sister around the house making a monster type noise and holding his hands in the air. We squealed and ran with delight. What little girl doesn't like to be chased? My father has continued this tradition with the grandchildren. My girls have only recently been converted to this tradition, but their Daddy has started a new twist: he puts a blanket over his head as he chases the girls around the house. The girls have tried to get Mommy to play monster, but I tell them mommies don't play monsters... that is a daddy game. Since Daddy has been super busy of late, the girls have started playing monster themselves. A few days ago, Bell had a pink blanket on her head and told me she was a monster.

Bell: Mommy, I'm a monster

Me: Oh... are you a pink monster?

Bell: No, I'm a blue monster.
Me: What do blue monsters eat?

Bell: Scared boys.

A few seconds later...

Bell: Mommy, I'm a pink monster.

Me: What do pink monsters eat?
Bell: Blue boys.

Clearly, we don't hang around enough boys as the girls are highly suspicious of them. The problem is, when we want them to be suspicious of boys (say around the age of 14 or 15), they won't be.