Preheat the oven to 350°F (or 325°F if using a dark or nonstick pan). Generously grease a 12-cup fluted tube cake pan with shortening and lightly flour it, or use a baking spray that includes flour.

In a large mixing bowl, combine the cake mix, chocolate milk, melted butter, eggs, sour cream, and the dry pudding mix. Mix with a spoon until everything is well blended; the batter will be very thick. Fold in the 2 cups of chocolate chips. Spoon the batter evenly into the prepared pan.

Bake for 56 to 64 minutes, or until the top springs back when gently touched in the center. Let the cake cool in the pan for 10 minutes, then carefully invert it onto a cooling rack or heatproof serving plate and remove the pan. Allow the cake to cool completely—this will take about 2 hours.

To make the ganache glaze, place 1 cup of chocolate chips in a small heatproof bowl. In a 1-quart saucepan, heat the whipping cream until it begins to simmer, then pour it over the chocolate chips. Let it sit for 5 minutes, then stir until the mixture is smooth. Drizzle the ganache over the cooled cake.

Top the cake by sprinkling 1½ cups of chocolate chips over the ganache. Drizzle caramel topping over everything, then finish by sprinkling with toffee bits and the chopped Snickers™ candy bar. Store the cake loosely covered at room temperature.