Mix the brownie mix, eggs, water and oil together in a bowl per the package instructions.
Pour the batter into a greased 11x7 inch glass baking dish. (The smaller pan size insures a deeper, fudgier brownie).
Use 2 knives (see @peas IGTV video to demonstrate the method) to the dollop the biscuits spread throughout the batter.
Use one knife to cover the biscuit spread with the batter.
Top with biscuit pieces, chocolate chips and marshmallows.
Bake at 350 for 25-30 minuets or until a toothpick comes out clean.