In a small bowl whisk together water, condensed milk, and vanilla instant pudding. Refrigerate for 30 minutes or until it sets.
Once it has set take it out of the fridge and add in the pumpkin puree and pumpkin spice and mix. Whip the whipped cream and fold it into the pumpkin pudding mix.
In a cup layer the bottom with ginger snap cookies, sliced bananas, and then the pudding mixture. Continue to layer until the pudding is finished.
Refrigerate the pumpkin spice banana pudding for 2 hours before enjoying it.