Preheat oven to 375 F.
Unroll the crescent roll dough and separate it into 4 rectangles, then press the perforations to seal.
Cut the dough with a sharp knife into strips 1/2 inch wide, and join 3 strips end to end to form one long “bandage”.
Wrap the “bandage” around a hot dog, leaving a gap near one end for the mummy’s face.
Repeat with all the hot dogs and arrange them on a baking sheet lined with parchment paper.
Bake until golden brown, 13 to 15 minutes. Start checking at 12 minutes, because the thin dough strips brown fast.
While the mummies are in the oven, cut slices of mozzarella as thick as you want the eyeballs to be.
Cut the sides off the olives so they lie flat.
Using the large straw, cut circles out of the cheese.
Cut the centers out of the cheese circles with the small straw.
Using the small straw, cut pieces out of the olives.
Place a little piece of olive into each cheese circle.
Take the mummies out of the oven, brush the face with a little mustard, mayo or ketchup, and press on the eyeballs.