Prepare cake as directed on the box using the water, oil, and eggs called for to make a 9x13” cake. Bake the cake in a 9x13” pan (that has been sprayed with cooking spray) according to the package directions.
While the cake is baking, place the ice cream in a large bowl and set it near the stove so it can melt.
When the cake comes out of the oven, let it cool 5 minutes. Then, using the back of a wooden spoon, poke several holes (about 30 or so) in the top of the cake. Hopefully by now your ice cream is mostly liquid. If not, microwave it for a few seconds until it’s all liquid or just some lumps of ice cream remain.
Pour melted ice cream over the top of the cake, making sure it gets in all the holes. Let the cake cool on the counter, then cover and chill for at least 2 hours or overnight. (It gets better the longer it sits!)
Before serving, frost the top with whipped topping or whipped cream and drizzle with ice cream toppings like chocolate and/or caramel sauce, sprinkles, and cherries.
Store covered in the refrigerator for up to 3 days.