Possessive much?

In the car on the way home, I'm sitting in the back next to Bean.  She looks towards me and I notice that she has something on her face.  I move to wipe it off and the following conversation ensues:

"Mommy, NO!"

"You have something on your cheek, lemme get it."

"What is it?"

"I think it's a boogie.  There, I got it"

"GIVE IT BACK!!"

Um...

Some kids are possessive of toys.  Mine?  Boogers.  Oh boy.