Preheat the oven to 350 degrees F. Prepare the chocolate cake mix according to the package directions. Pour the batter into a greased 9-inch x 13-inch baking dish. Bake for 28-33 minutes.
Remove the cake from the oven and let it cool completely. Use the back of a wooden spoon to poke holes across the entire top of the cake.
Pour the dulce de leche over the cake, saving a small amount for topping later. (If needed, heat the dulce de leche in a bowl in the microwave to make it easier to drizzle.) Using a knife, spread the caramel over the cake, making sure it gets in all of the holes.
Place the cake in the refrigerator for 1 hour.
Remove the cake from the refrigerator and spread the chocolate frosting over the top of the cake. Sprinkle the top with chopped pecans and chopped turtle candies. Then drizzle the remaining dulce de leche over the top.