Place cake mix in a mixing bowl; add buttermilk, water, oil, and eggs. Mix for 30 seconds on low, scrape the sides of the bowl, then mix for 2 more minutes on medium.
Place in a greased 9x13 pan and bake 30-32 minutes, or until a toothpick inserted into the center comes out clean. Cool completely.
Using a wooden spoon or another spoon that has a long, thin, round handle, insert the handle into the cake to create holes all over it. Space the holes out about 2 inches.
Pour entire can of sweetened condensed milk over the cake, allowing it to get into the holes. Then do the same thing with the caramel, using only half the jar.
Cover cake with Cool Whip. Then sprinkle chunks of Snickers Minis over the Cool Whip. Serve with drizzled caramel and chocolate sauce.