Preheat the oven to 400°F. Peel and dice the apples. Sprinkle with brown sugar and cinnamon. Set aside.
Follow the directions on the box of puff pastry to thaw. Unfold the two sheets of puff pastry and cut each sheet into four squares. Place the squares on a cookie sheet lined with parchment paper.
Score three dividing lines as shown in the picture per square. Next create 6-8 strips on each side of the square being careful not to cut into the middle.
Place a spoonful of your sugar cinnamon diced apples in the middle of the square. Next, fold the top strip and bottom strip down each side of the middle to keep the apples in place. Fold the remaining strips diagonally to create the body of the mummy. Be sure to leave enough space around the head of the mummy to fit candy eyeballs once the pastries come out of the oven.
Beat the egg in a small bowl and use a pastry brush to spread the eggwash over the top of the mummy. Sprinkle each mummy with equal parts cinnamon and sugar.
Bake according to the package directions, about 15 to 20 minutes until the mummies are golden brown. Remove from the oven and allow the pastries to cool before fitting in the candy eyeballs.