Preheat oven to 325 degrees and spray a 9x9 inch metal baking pan with non-stick spray then line with parchment paper.

In a large bowl, whisk together the sugar, cocoa powder, flour, xanthan gum, baking soda, salt, and cornstarch.

Make a well in the center and add the eggs. Beat the eggs and mix in the butter, oil, vanilla extract, and water. Mix until the dry ingredients are incorporated.

Transfer the batter to the prepared pan and bake at 325 degrees for 22-25 minutes. Cool completely then refrigerate until firm before cutting.

Once chilled completely, slice the brownies into 16 squares and set on a wax paper-lined baking sheet or large cutting board.

Melt the chocolate chips in a microwave-safe bowl and stir in the oil as needed – you want a pipeable consistency, but it shouldn’t be too thin so it doesn't run off the brownies.

Transfer the melted chocolate to a disposable piping bag and snip the tip off.

Pipe the “bandages” onto the mummies and then place two eyes on each mummy to decorate.

Let the chocolate harden before serving (you can speed it up by placing them in the refrigerator or freezer for a few minutes).