In medium bowl, beat together peanut butter, cream cheese and sugar. Gently fold in 3 cups whipped topping. Spoon mixture into prepared pie shell. Using spatula, smooth mixture to edges of pie.
Reserve 2 tablespoons hot fudge topping and place remainder into microwave safe bowl or glass measuring cup. Microwave for 1 minute, then stir. Spread hot fudge topping over pie to cover peanut butter layer. Refrigerate until serving time.
Just before serving, spread remaining whipped topping, over hot fudge layer, being careful not to mix the two layers. Place reserved 2 tablespoons hot fudge topping in a small baggie and knead for a few seconds. Cut tiny hole in corner of bag and drizzle over pie. Repeat with 2 tablespoons peanut butter, drizzling in opposite direction of hot fudge topping.