Why one should never scratch moles...

Children make everything interesting.  They have insights on food, exercise, and even eating habits that astonish me and, yes, make me think.  A good example of this happened today, actually.

There I was, sitting in front of our living room window, staring outside at the sunny front yard and praying that the six loads of laundry sitting next to me would fold themselves, when I hear a sudden running around upstairs.  Now.  For those of you who know my house--very few, yes--there has always been this one spot in my bedroom where, if you step on it just right, it will make a very loud boom...  Sort of like a train wreck.  So I hear someone run through the room and into the hallway screeching their head off, and then another person do the same thing.  It was David.  Apparently, he and Madeline had been chasing eachother over a mole.  A mole, you ask?  Why a mole? 
This is what David had to say when he was finally corner.
David: "Don't scratch my mole off!"
Goo:(giggleshystericallylikeagirl)  "Why not?!"
Dave:(in a low, secretive voice) "...  If you pull moles off, you get cancer."

...  Ummmm...  Wow?  Needless to say, I sat there laughing my head off for several minutes afterwards and listening to the rest of their conversation made my folding go a bit faster.