In a large saucepan combine marshmallows and margarine. Cook and stir over medium-low heat until mixture is melted. Gradually stir in cereal until well combined.
Using 1/2 to 1 cup of the cereal mixture for each, form into ghost shapes. Place on parchment or waxed paper-lined baking sheet or tray and cool completely.
Dip each ghost shape into melted candy coating. Replace on lined tray. Use pieces of licorice, chocolate sprinkles, and/or chocolate pieces for the eyes, nose, eyebrows, and mouth. Let stand until set.