In a medium bowl mix the butter and extract together until well combined.
Slowly add in the powdered sugar a little at a time.
Whip until frosting is smooth with no lumps.
Add in milk a tablespoon at a time until it thins out the frosting a little.
Fit a pasty bag with a flat edged tip and fill bag with frosting.
Pipe strips in a criss cross pattern over the top of the brownies making it look like mummy wrappings.
Place candy eyes in a random pattern, gently pressing them down into the frosting.
Using a large sharp knife, cut the brownies into equal squares or rectangles.