Prepare cake as directed on the box and bake in a 9-x-13-inch baking dish.
Let cool for 15 minutes.
Poke cake with a fork at ½–1-inch intervals.
Use hot and cold water to make Jell-O as directed on the package.
Spoon Jell-O liquid over the cake gradually until it is all absorbed.
Chill in the refrigerator for 3–4 hours. Top with whipped topping right before serving. ENJOY