Dirty rat

The boys, holding a toy block: Can we throw this away?
Me: No. Why?
Thing One: It has a dirty rat on it.
Me: What are you talking about?
Thing Two: This (points to an outline of a mouse).
Me: No. We're not going to start throwing away toys. If we throw away the toys we won't have any toys left to play with.
Thing Two: Can we die the dirty rat with that purple thing? (Translation: Can we kill the picture of the mouse on our block with the fly swatter?)