Preheat the oven to 350℉.
In a bowl, mix the spice cake mix and the pumpkin pie filling together. Spread that out in a baking pan, it'll be a bit then but it's going to rise.
Bake in the oven for 25-30 minutes or until the cake is cooked through. You can test this with a toothpick through the center. If it comes out clean the cake is ready.
Remove from the oven and allow to fully cool.
Once cooled, poke holes over the cake and fill the holes with the condensed milk. Take your time to allow the milk to go into the holes and not all of it run to the sides of the cake.
Next, spread the cool whip across the top, add the Heath bars and drizzle the caramel. Cover the cake and allow the cake to sit for about 2 hours or make it ahead and serve the next day. Cake is best serve chilled, enjoy.