Melt chocolate in microwaveable bowl on HIGH 1 min., stirring after 30 sec. Stir until chocolate is completely melted. Use clean small paintbrush to paint a ghost face on inside of each of 4 clear 8-oz. plastic cups with the melted chocolate. Refrigerate until ready to use.
Place milk and dry pudding mix in 1-qt. pitcher with tight-fitting lid; cover. Shake vigorously 1 min. or until well blended.