Combine the ricotta cheese, mozzarella cheese, garlic powder, basil, mushrooms and olives into a large bowl, including the meatballs (reserving a few meatballs and sliced olives for the mummy eyes) and mix together.
Divide pizza dough into 8 equal dough balls.
Roll out dough into small circles, and place a nice helping of Ricotta mixture in the center.
Take a knife and make slices in the dough horizontally along the sides of the mixture, leaving a larger slice on the top and bottom.
Fold the bottom of the calzone up towards the top.
Start over-lapping the dough across the body of the mummy from the bottom working your way up to the top.
Leave room for the eyes (two meatballs with olives) to stick out the top. Place on a pizza pan or baking sheet.
Brush with a lightly beaten egg and bake for 30 minutes.
Serve with a small dish of marinara or spaghetti sauce.