bake cake as directed in 9x13" pan

let cake cool for about 2-3 minutes and poke holes with the stick of a wooden spoon or something of that size

in bowl whisk together pudding mix and 4 cups milk. let sit just to slightly thickened (still able to pour)

pour over cake, spread with back of spoon being sure to push into holes.

refrigerate cake until completely cooled.

slice bananas over pudding top and then spread whipped topping

crush up wafers, leaving a few larger pieces for crunch. sprinkle over cake. this step can be saved until right before serving so cookies keep their crunch.