Preheat your oven to 400°F and spray the skull-shaped pan generously with nonstick cooking spray. Unroll your pizza dough onto a lightly floured surface and gently roll or stretch it into a large, even rectangle.
Slice the dough into six equal strips using a sharp knife or pizza cutter. Lay one strip into each skull cavity, pressing it gently into the grooves so the eyes, nose, and teeth details show through.
Spoon a little pizza sauce into the center of each dough-lined cavity, then layer in shredded mozzarella, a sprinkle of Parmesan, mini pepperoni, and a pinch of Italian seasoning. Keep the fillings centered so the dough can still fold and seal properly.
Fold the overhanging dough over the filling, pinching the edges together to seal each skull closed. Pop the tray in the fridge for about 10 minutes, since chilled dough holds its shape much better once it hits the hot oven.
Bake the skulls for 16 to 20 minutes, or until the tops turn a light golden brown. Let them rest in the pan for about 5 minutes before carefully popping them out onto a cooling rack.