Preheat oven to 350 degrees. Spray a 9x13 baking pan with non-stick cooking spray.
In a large mixing bowl, add in the box cake mix, vegetable oil, eggs, chocolate pudding and sour cream. Mix with a hand mixer until incorporated.
Spread the cake batter into the prepared pan.
Place into the preheated oven. Let bake for 40 minutes or until done. Place a toothpick into the center of the cake and if moist crumbs come out it's done. You don't want batter on your toothpick. That means your cake isn't done.
Remove from the oven and let cool.
Poke large holes into the cake with large straws. You can also use the round handle of a slotted spoon if you happen to have one on hand.
Heat up one of the 11.75 ounce jars in the microwave for 45 seconds. Stir and pour the fudge into the large holes that you made into the cake. Spread the fudge to be sure to fill the holes.
Place ¼ cup of the chocolate syrup on top of the cake.
In a large bowl, add in the whipped topping and the remaining jar of hot fudge. Stir until thoroughly combined.
Spread the whipped topping onto the cake evenly.
Drizzle the remaining ¼ cup of chocolate syrup on top of the chocolate whipped topping.
Sprinkle the mini chocolate chips on the top of the chocolate syrup and whipped topping.
Cover and place into the fridge. Cut and serve. Store in the fridge!