Stir together 1/4 C corn syrup, brown sugar and butter in a saucepan. Cook over low heat, stirring occasionally, until mixture begins to boil.
Remove from heat.
Pour over Rice Krispies, stirring until coated.
Pour mixture into a greased 9 inch round pie plate form a crust. Press up on the sides.
Stir together peanut butter, fudge sauce and 3 Tbsp corn syrup.
Heat mixture on stove top or microwave.
Spread a few tablespoons of the mixture on the bottom of the crust.
Spoon softened ice cream into crust, spread evenly.
Freeze until firm.
Reheat fudge mixture if needed and spread over the top of the ice cream. If it is warm, work quickly as the ice cream will begin to melt.
Sprinkle with chopped up peanut butter cups.
Freeze until ready to serve
Spread a thin layer on the bottom of the crust.