In a saucepan, melt margarine and marshmallows. Mix until melted and smooth. Add orange food coloring. Stir until desired shade. In a mixing bowl, combine cereal, candy corn, and chocolate chips. Add marshmallow mixture to cereal mixture, stirring quickly. Spread on a large buttered jelly roll pan; press with floured hands. While still warm, press on candy pumpkins spaced two inches apart. Refrigerate until ready to serve. Cut into squares.