Grease 13x9-inch pan. In 4-quart saucepan or Dutch oven, combine peanut butter, honey, margarine and marshmallows. Cook over low heat until marshmallows are melted, stirring occasionally. Carefully stir in cereal and candy corn.
With wet or greased spatula, spread mixture in greased pan. Cool 15 minutes or until completely cooled. Cut into bars.