Heat oven to 350°F. Place cereal in resealable food-storage plastic bag; seal bag and crush with rolling pin.
In ungreased 9-inch microwavable pie plate, mix butter and 1 tablespoon peanut butter. Microwave uncovered on High 30 seconds; stir until blended. Stir in crushed cereal until evenly coated. Press evenly on bottom and up side of pie plate. Bake 10 minutes. Place in freezer.
Make pudding mix as directed on box for pie filling, except after cooling 5 minutes, add 2 tablespoons of the 1/4 cup peanut butter; stir a few times just until melted and marbled throughout. Pour into crust.
In microwavable measuring cup, microwave remaining 2 tablespoons peanut butter uncovered on High 30 seconds. Drizzle over pie. Refrigerate at least 3 hours but no longer than 24 hours until filling is set.