PREPARE brownie mix according to package directions using oil, milk and eggs; cool completely. Cut pan of brownies in half; cut each half into quarters. Combine pudding mix, milk and sweetened condensed milk in medium bowl; mix until smooth. Reserve 1/2 cup whipped topping for garnish; mix remaining topping into pudding mixture.
BREAK up half of the brownies, placing them into the bottom of a 14 cup trifle or glass bowl. Top with half of the filling. Place 2 tablespoons hot fudge topping into a resealable plastic bag; reserve for garnish. Heat topping according to the label directions; spoon all but reserved topping over filling. Reserve 7 cherries for garnish; spoon remaining cherry filling over fudge topping. Top with remaining brownies and filling.
DOLLOP reserved whipped topping into center of trifle; mound with cherries. Heat bag of hot fudge topping in microwave on HIGH (100% power) 7 to 10 seconds. Cut a small corner off bag; drizzle topping over trifle. Sprinkle with decors or sprinkles. Refrigerate 6 hours or overnight.