Preheat the oven to 180°C (350°F/Gas Mark 4).
Cut each muffin in half to make 4 rounds pizza bases. Place them cut-side up on a baking tray.
Spread a thin layer of tomato puree over the cut sides of the muffins.
Using a round cutter that is roughly the same size as the muffin, cut 4 circles from the mozzarella cheese slices. Cut each circle into approx. six strips.
Arrange a set of cheese strips on the top of each muffin, layering them at different angles to create a mummy effect.
Slice the black olives into rings.
Arrange two black olive rings on the top of each pizza for eyes.
Bake in the oven for 5-10 minutes until the cheese is just melted.
Leave to cool for a few minutes before serving, or cool completely and pack in a lunch box.