What, exactly, is going on inside that little head?

My daughter last night, apropos of nothing, turns to me while brushing her teeth and says:

"You know, if you're looking in the mirror, you pretty much can't be attacked by ninjas."

she then stops, walks behind me, and starts to tickle me, and says,

"Unless the ninja is WAY smaller than you!"

She goes back to brushing her teeth and absently begins to hum the Enzyte jingle again (I wonder if the people who wrote that thing know that it's addictive to children?).

She's thoughtful for a minute and then says,

"I wonder if Smilin' Bob ever has trouble with ninjas. He's pretty weird."