Part 1: Baking the Perfect Brownie Lair

1. Preheat and Prepare: Preheat your oven to the temperature specified on your brownie mix box, typically 350°F (175°C). Grease and flour a 9×13 inch baking pan, or line it with parchment paper, leaving a 2-inch overhang on the sides. The parchment paper sling is a game-changer, allowing you to lift the entire slab of brownies out for easy cutting.
2. Mix the Potion: In a large mixing bowl, combine the brownie mix, water, oil, and eggs. Stir with a wooden spoon or spatula until just combined. Be careful not to overmix! Overmixing develops the gluten in the flour and can lead to tough, cakey brownies instead of the dense, fudgy texture we want for this recipe. A few small lumps are perfectly fine.
3. Bake to Perfection: Pour the batter into your prepared baking pan and use the spatula to spread it into an even layer, making sure it reaches all the corners. Bake according to the package directions for a 9×13 inch pan. The key to a great brownie is to slightly underbake it. To check for doneness, insert a wooden toothpick into the center of the brownies about 2-3 minutes before the recommended bake time is up. It should come out with moist, fudgy crumbs attached, not wet batter. If it comes out completely clean, they are likely overbaked.
4. The Crucial Cool Down: This is the most important—and most difficult—step! You must let the brownies cool completely in the pan on a wire rack. This can take at least 1-2 hours. Attempting to cut warm brownies will result in a crumbly, gooey mess. Patience is your magical ingredient here. Once fully cooled, use the parchment paper overhangs to lift the brownies out of the pan and onto a cutting board.

Part 2: Assembling Your Colony of Bats

1. Create the Bat Bodies: Using a sharp knife or a round cookie cutter (approximately 1.5 to 2 inches in diameter), cut the brownies into 12-15 circles. If you don’t have a round cutter, you can simply cut the brownies into squares or rectangles. The bat shape is forgiving!
2. Craft the Bat Wings: Take your chocolate sandwich cookies. Gently twist them to separate the two halves. Scrape the creme filling off one side (feel free to “dispose” of the evidence!). Take the plain chocolate cookie wafers and carefully cut each one in half with a sharp knife. Use a gentle sawing motion to prevent them from shattering. Each half-wafer will become one bat wing.
3. Bring the Bats to Life: Now for the fun part! Take one of your round brownie “bodies.” Dab a small amount of chocolate frosting on the straight edge of one of your cookie “wings” and gently press it into the side of the brownie. Repeat on the other side to create a pair of wings. The frosting acts as a strong, edible adhesive.
4. Give Them Sight: Dab two tiny dots of frosting on the top-center of the brownie body. Gently press two candy eyeballs onto the frosting dots. Your bat can now see!
5. Repeat and Display: Continue this process for all your brownie circles until you have a full colony of bats. Arrange them on a platter and watch as your spooky, delicious creations take flight!