Unwrap granola bars and place in a food processor. Pulse until fine crumbs form. Add melted butter and sugar, pulse to combine.Pour half of the crumb mixture into the bottom of an 8x8-inch baking dish. Press flat.In a stand mixer fitted with a beater attachment, mix together whipped topping, marshmallow fluff, and softened cream cheese until light and whippy. Spoon half of this mixture on top of the crumb crust in the baking dish. Spread hot fudge sauce on top of this layer, then layer with remaining marshmallow fluff and top with remaining crumb crust.Cover with tin foil or plastic wrap. Place in freezer for 2 hours until frozen. Serve by slicing into squares. Enjoy!