1. Place one rack in lowest part of oven and one in lower-middle and heat to 450 degrees F. Line two baking sheets with parchment and set aside.
2. Divide dough into six pieces and cover with plastic or a clean kitchen towel. Working with one piece at a time on a lightly floured surface, use fingertips to press dough outward from the center to form crust, then stretch evenly into a 6" round. Transfer to prepared baking sheet and repeat with remaining dough. (If dough shrinks back when stretching, cover and let rest 5 to 10 minutes, then try shaping again.)
3. Brush rounds all over with oil, then spread 1 to 2 tablespoons sauce evenly over each, leaving edge of crust bare, then decorate with desired toppings. To make ghosts: Cut mozzarella into ghost shapes, then arrange on top of sauce. After baking, place two small pieces of black olive on each ghost to form eyes. To make eyeballs: Cut mozzarella into 1" circles and arrange on top of sauce. Slice Spanish olives crosswise, then place one slice on each piece of cheese. Slice pepperoni into thin strips, then arrange three to four strips around each olive slice pointing outward. To make spiders: Halve black olives lengthwise; arrange one half on top of sauce to form the body of each spider, then thinly slice remaining pieces crosswise and arrange on either side of body to form legs.
4. Transfer baking sheets to oven and bake until bottoms are golden brown and tops are bubbling, 12 to 15 minutes. Let sit 5 minutes before serving.