Preheat the oven to 350°F (180°C). Line a 9 × 13-inch baking pan with parchment paper, leaving an overhang for easy removal.
In a large bowl, combine the brownie mix, vegetable oil or melted butter, water, and eggs. Stir until smooth and fully blended.
1 box milk chocolate brownie mix, ½ cup vegetable oil or melted butter, 3 tablespoons water, 3 large eggs
Pour the batter evenly into the prepared pan. Bake according to the package directions, or until a toothpick inserted near the center comes out with just a few moist crumbs.
Lift the brownies out of the pan using the parchment paper and allow them to cool completely on a wire rack.
Once cooled, use a football-shaped cookie cutter to cut out brownie shapes. Gather and re-press scraps if needed.
In a small bowl, mix the powdered sugar and milk until smooth and pipeable. Add additional milk a teaspoon at a time if needed.
1 cup powdered sugar, 1 tablespoon milk
Transfer the icing to a piping bag or a small zip-top bag. Pipe icing onto the brownies to create football laces.