Combine peanut butter and corn syrup in a bowl; heat in microwave until it can easily be stirred into a smooth mixture, 1 to 2 minutes.

Stir crushed cereal into the peanut butter mixture; spread into a pie plate to make a crust.

Spoon softened ice cream over the crust and smooth into a flat layer. Drizzle chocolate syrup over the ice cream layer.

Put pie in freezer and freeze until firm in the center, at least 30 minutes.