Mix the cake mix, water, vegetable oil, eggs, vanilla extract and 1/2 of the sweetened condensed milk together in a large bowl.
Spray a 6 quart crock pot with a non-stick cooking spray.
Pour the batter into the crock pot and top with the chocolate chips.
Cover and cook on high for 2-3 hours. Check the cake after 2 hours as each crock pot cooks differently.
When the cake is done baking use the round handle end of a wooden spoon and poke holes all throughout the cake.
Pour the remaining sweetened condensed milk all over the top of the cake and spread it out.
Then pour the caramel sauce over the top of the cake and spread it out.
Remove the crock pot insert from the crock pot and allow to cool at room temperature and then move to the refrigerate to chill for at least 30 minutes.
Serve topped with the cool whip and chopped up heath bars and enjoy!