Grab a cookie sheet and spray with cooking spray. Then unroll the crescent dough in a flat sheet. Then in the center line up the cheese overlapping it. Then lay the ham on top of the cheese overlapping it as well.
On both sides of the ham and cheese cut about 1 inch slits. Repeat until there is slits all the way down on the left and right of the ham and cheese. Then starting at the bottom fold in one side at a time. Creating a criss-cross pattern.
Once all the sides are folded on top of the ham and cheese. Take the egg and water and whisk it together. To create an egg wash. Then brush the egg wash lightly on top of the criss-cross dough pattern.
Then in an oven pre-heated until 375 degrees F pop the mummy in and cook for 18-20 minutes. Or until lightly golden brown and cooked all the way through. Then serve