Preheat oven according to brownie mix box instructions. Grease a 9x13-inch pan.

Prepare brownie batter using the mix and egg. Pour into the prepared pan and bake according to box directions.

Allow brownies to cool completely before layering.

Beat the softened cream cheese until smooth. Gradually add the powdered sugar while mixing.

Fold in one container of whipped topping until creamy.

Spread the cream cheese mixture evenly over the cooled brownie layer.

In a separate bowl, whisk together the instant chocolate and vanilla pudding mixes with the milk until thick.

Pour the pudding mixture over the cream cheese layer and spread evenly.

Top the pudding layer with the second container of whipped topping.

Sprinkle the grated Hershey bar or drizzle chocolate syrup over the top.

Cover and refrigerate for at least 4 hours, or overnight for best results.

Slice and serve chilled.