1Heat oven to 350°F (325°F for dark or nonstick pan). Grease bottom only of 13x9-inch pan with shortening or cooking spray.
2Make brownies as directed on box for cakelike brownies, for 13x9-inch pan. Cool completely, about 1 hour.
3In medium bowl, beat marshmallow creme, peanut butter and milk with electric mixer on medium speed until smooth and creamy. Spread over cooled brownies. Sprinkle with candies and peanuts.
4In small microwavable bowl, microwave chocolate chips and oil uncovered on High 30 to 60 seconds, stirring once, until melted. Drizzle over brownies. Refrigerate about 15 minutes or until chocolate is set. For brownies, cut into 6 rows by 4 rows.