In a bowl, mash the banana fully. Mix in the peanut butter, pumpkin purée, oats, chia seed, vanilla, pumpkin pie spice, cinnamon, and sea salt. Stir to combine.
Add a lid and allow to sit in the fridge overnight (or at least for 2 hours). When the liquid absorbs into the pumpkin oatmeal you’ll be left with a pudding-like consistency.