CUT 4 cookies crosswise in half; reserve for later use.
CHOP remaining cookies. Add to ice cream; mix well. Freeze 1 hour or until firm.
SCOOP ice cream mixture into 16 small balls; place in single layer on parchment-covered baking sheet.
PLACE 1 scoop ice cream mixture in each of 8 (6-oz.) glasses. Tilt each glass, then slowly pour 4 oz. root beer over ice cream. Top with whipped topping and remaining ice cream scoops.