Preheat oven to 350 degrees F. Line a muffin tin with cupcake liners. Set aside.

In a large bowl, using a hand-held mixer or stand mixer with a paddle attachment, cream butter. Add both sugars and continue beating until light and fluffy. Mix in eggs, one at a time, mixing well after each addition and scraping the sides of the bowl as needed. Add vanilla extract and bananas and mix well. Set aside.

Meanwhile, stir together 2 cups flour, baking powder, baking soda and salt. Add flour mixture alternately with buttermilk to banana mixture. Beating just until blended.

In the bowl, toss together chocolate chips with remaining 1 tablespoon flour. Stir chocolate chips into batter.

Divide batter evenly among 20 paper lined muffin cups. Bake for 18 to 22 minutes or until toothpick inserted in center comes out clean.

Let cupcakes cool in muffin pan for 5 minutes, then remove to a wire rack to cool completely. Once cupcakes are completely cool, using a large round tip, pipe peanut butter frosting on top of cupcakes. Place colored sprinkles in a small bowl. Carefully roll edges of frosted cupcakes in sprinkles. Top cupcakes with two pieces of chocolate candy bars (to form book) and one gummy worm.

For Peanut Butter Buttercream Frosting:

In a large bowl, using a hand-held mixer or stand mixer with a paddle attachment, cream butter and peanut butter until smooth and creamy. Beat in the vanilla. Slowly add in the powdered sugar one cup at a time alternating with one tablespoon milk, mixing until desired consistency is reached.