Spray the bottom of a 9x5-inch loaf pan with non-stick cooking spray and line with plastic wrap. Allow enough plastic wrap to wrap over the top.
Spread a layer of whipped topping over the bottom of the pan; then a layer of graham crackers, more whipped topping, a layer of sliced bananas, and finally a layer of chocolate; repeat layers and cover with whole graham crackers.
Bring plastic wrap up over the top and cover. Freeze for at least 4 hours. To serve, invert the pan onto a plate, and remove plastic wrap. Sprinkle with 2 Tbsp. graham cracker crumbs or chocolate shavings, slice, and enjoy!