01 - Preheat oven to 400°F and line a baking sheet with parchment paper.
02 - On a lightly floured surface, roll out pizza dough to 1/4 inch thickness.
03 - Using a ghost-shaped cookie cutter or a template with a sharp knife, cut out 16 ghost shapes from the dough, gathering and rerolling scraps as needed.
04 - Arrange 8 dough ghosts on the prepared baking sheet. Spoon 1 to 1 1/2 tablespoons of pizza sauce onto each, leaving a 1/2 inch border clear.
05 - Sprinkle with shredded mozzarella, mini pepperoni if using, oregano, garlic powder, and a pinch of salt and pepper.
06 - Lightly brush water around the borders. Place remaining dough ghosts on top, press edges to seal, and crimp with a fork.
07 - Gently press two black olive slices into the top of each for eyes. Brush tops with olive oil and, if desired, cut a small slit for the mouth.
08 - Bake for 18 to 20 minutes, or until golden brown and puffed.
09 - Allow to cool slightly before serving. Serve with extra pizza sauce for dipping if desired.