Rogue's Skipping Stones

I weighed a thick, palm-sized disc of black slate in my hand, sizing up the glassy stretch of the lagoon. Ordinary skimming is for kids, sugar, but launching a heavy river slab across forty yards of open water? That's my kind of morning drill. I dropped low on my heels, cocked my arm back, and whipped that slate with everything in my shoulder. It hit the surface with a sharp crack, skipping four furious times and kicking up rooster tails of spray before smacking a rotting driftwood stump clean off the opposite sandbar. That ought to let whatever's lurking beneath the surface know who's awake.