Place milk, candy bars and marshmallows in top pan of double boiler.Melt.(or just use a large pan set in a pan of boiling or simmering water.Chocolate will stick and burn if pan is next to the burner.) When melted, set out of water to cool completely.Fold topping into chocolate.Pour into pie crust and chill in refrigerator for at least 3 hours or until ready to serve.