The Banana Pudding Parfait features a layer of crushed vanilla wafers, a layer of banana pudding, and a layer of whipped cream topped with a vanilla wafer (possibly of the Nilla brand) and a sprinkle of crushed vanilla wafers.
The dessert is not all that common in fast food and is more of a regional Southern dish. Chick-fil-A offered a Banana Pudding Milkshake a few years back but haven't brought it back since.
Prices vary but they have these for $1.69 in my area. The parfait is available for a limited time through December, while supplies last.