Heat oven to 450°F. Unroll crust into 9-inch pie pan; crimp edges; prick bottom with fork. Bake at 450°F for 9 to 11 minutes. Let cool.
Meanwhile, finely chop 1 ounce of chocolate; set aside for garnish. Coarsely chop remaining 3 ounces of chocolate and place in a nonstick saucepan along with pudding mixes. Slowly stir in milk.
Cook over medium heat, stirring constantly until the mixture reaches a full boil and is very thick. Remove from heat and quickly stir in mashed bananas.
Pour into the cooled 9-inch pie shell. Cover filling directly with waxed paper to prevent skin from forming and refrigerate until set, 4 hours or overnight.
To serve pie, remove and discard waxed paper. In medium-size bowl, beat cream and confectioners sugar until stiff. Spread over pie filling and sprinkle reserved finely chopped chocolate over whipped cream. Garnish with additional banana slices, if desired.