Shell

"Old hunter recipe," Butch said.  "Roast turtle.  Ingredients: one turtle, one campfire.  Put the turtle on the fire; when the shell cracks, it's done."  He stirred the embers and shoved a few more sticks into the wavering red heart of the flame.  "You got to crack the shell to get at the meat anyway, right?" 

The scaly feet waved in the smoke.

"Is the shell there to keep us out?" Caleb wondered.  "Or is it to keep something else in?"

There was a sudden, sharp crack, like a gunshot.  The flames roared as the wind came down.  Then silence.