Prepare cake batter and bake as directed on package for 24 cupcakes. Cool completely.
Beat pudding mix and milk with whisk for 2 minutes. Let stand 5 minutes.
Meanwhile, use serrated knife to cut cupcakes horizontally in half. Stir 1/2 cup whipped topping into pudding; spoon about 1 tablespoon onto bottom halves of cupcakes. Cover with cupcake tops.
Microwave remaining 1 cup whipped topping and chocolate in small microwaveable bowl on high 1-1/2 minutes or until chocolate is almost melted, stirring after 1 minute. Stir until chocolate is completely melted and mixture is well blended. Let stand 15 minutes. Spread onto cupcakes.
Refrigerate 15 min. before serving. Refrigerate leftovers.
Cook's Note: Serve frosted cupcakes in colorful paper muffin cups.