1. Preheat the oven to 350°F (175°C).

2. In a large bowl, mix together the cake mix, water, oil, and eggs until well combined.

3. Pour the batter into a greased cake pan and bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.

4. Remove the cake from the oven and let it cool completely.

5. Once the cake has cooled, spread a layer of chocolate ice cream on top of the cake.

6. Peel and slice the bananas, then arrange them on top of the ice cream.

7. Place the cake in the freezer for at least 2 hours to allow the ice cream to set.

8. Remove from the freezer and let it sit at room temperature for 5 minutes before serving.

9. Slice and enjoy!