1. Prepare cake mix and bake in 9x13 pan.
2. Poke holes in cake.
3. On stove top, heat sugar, milk, 1/2 of the coconut until the sugar is melted. Pour over warm cake.
4. When the cake is cooled, frost with thawed whipped topping and the remaining coconut.
5. Refrigerate.
6. It tastes better if it is made 1-2 days ahead of time.