Like a lot of writers, I have many random notes for story ideas, most of which go nowhere or sit in a notebook for years before they actually become a story. "Under a Rock" started as one of those: I had the idea of an inexplicable gigantic tooth showing up in someone's backyard, and them charging admission to see it, a la "A Very Old Man With Enormous Wings." I plucked the idea out of my notebook after seeing an anthology call that had something to do with sharks and dinosaurs; I decided th...