Cook white chocolate in medium microwave safe bowl on high power, 2 - 3 minutes or until smooth when stirred, stirring every minute. Cool slightly.
Stir in marshmallows; mix lightly until completely coated. Drop by spoonfuls onto wax paper-lined tray. Smooth and flatten to make ghost shape. Decorate with candies and/or decorator icing to make faces, if desired. Store at room temperature.