Preheat your oven to 400°F (200°C) and let the frozen puff pastry sheets defrost at room temperature for about 15-20 minutes.

Use a ghost-shaped cookie cutter to cut out four ghosts from each sheet, placing them on a parchment-lined baking sheet.

Spoon marinara sauce into the center of half of the ghost shapes, leaving a ¼-inch border around the edges.

Sprinkle pepperoni slices and add shredded mozzarella cheese on top of the marinara sauce.

Cut eyes and a mouth in the remaining ghost shapes and place them on top of the sauced pieces.

Press the edges of the pastries to seal them together, crimping with a fork for a decorative touch.

Mix a tablespoon of water with a beaten egg to create an egg wash and gently brush it over the surface of each ghost.

Bake in the preheated oven for 13-15 minutes until golden brown and flaky.

Remove from the oven and let cool for 3-5 minutes before serving with marinara sauce for dipping.