Spray a 13 x 9-inch baking pan with nonstick cooking spray. Heat marshmallows and butter in large saucepan over medium heat, stirring frequently, until marshmallows are melted; remove from heat. Stir in peanut butter until combined. Stir in cereal and chopped Butterfinger Bites until coated. Spread into prepared pan. Cool completely; cut into bars. Enjoy!