Flight of the Bats. (I have done this the past two years, and it always looks AMAZING. Idea: This last year I sprayed GID spray on them, and added a black light to my hallway. The effect was beyond perfect!
Spray-paint the rind a matte black and let dry. Use a spoon handle to scratch away paint to create stars, moons, and spirals. Add water and blooms. (via Pumpkin Decorating - No Carve Pumpkin Decorating Ideas - Good Housekeeping )