Beat together 1 cup peanut butter, cream cheese and sugar in a medium bowl with an electric mixer on medium, until well combined. Gently mix in 3 cups whipped topping until thoroughly combined. Spoon mixture into pie shell. Using a spatula, smooth mixture to edges of pie.
Reserve 2 tablespoons of hot fudge topping into the corner of a resealable plastic bag. Microwave remaining topping, on HIGH (100% topping), for 1 minute. Stir. Spread topping over pie, covering entire peanut butter layer. Refrigerate until set. Spread remaining whipped topping (1 1/2 cups), over hot fudge layer, being careful not to mix the two layers.
Cut a small corner from bag containing topping. Squeeze bag to drizzle topping over pie. Place remaining 2 tablespoons peanut butter in a resealable food storage bag; cut bag corner and squeeze to drizzle in opposite direction from topping. Refrigerate until ready to serve.
