Prepare and bake pie crust according to the directions on the box. Cool completely.
In a small microwave-safe bowl, melt chocolate on 50% power until smooth. In a separate small bowl, heat heavy cream for 10 seconds. Pour cream into chocolate and stir slowly until fully incorporated. Pour chocolate mixture over bottom cooled crust. Refrigerate 10 minutes to set the chocolate. Slice bananas 1/2 in. thick and place in a single layer over the chocolate.
In a medium bowl, combine pudding mix, milk, and rum extract. Whisk for 2 minutes, or until completely dissolved and beginning to thicken. Pour over bananas. Chill for 30 minutes.
In the bowl of an electric mixer, whip heavy cream and confectioners' sugar until cream holds soft peaks. Spread the whipped cream over the top of the pie. Garnish with whipped cream rosettes and grated chocolate, if desired.