ADD boiling water to gelatin mix in medium bowl; stir 2 min. until completely dissolved. Add enough ice cubes to cold water to measure 1-1/4 cups. Add to gelatin; stir until slightly thickened. Remove any unmelted ice. Refrigerate gelatin 15 to 20 min. or until set but not firm; stir vigorously to create "bubbles."
PLACE chopped wafers in 4 clear plastic cups; cover with marshmallows and gelatin.
REFRIGERATE 1 hour or until firm. Top with candies just before serving.