Preheat the oven to 350F. Generously grease a 12-cup bundt cake pan and lightly flour (or use baking spray).
In a large bowl, combine the cake mix, chocolate milk, butter, eggs, sour cream and pudding mix. Mix until combined (the batter will be thick). Stir in the chocolate chips. Spoon into the prepared pan.
Bake until a tester inserted in the center comes out clean, 40 to 50 minutes. Cool 10 minutes. Turn the pan upside down onto a serving plate; remove the pan. Allow the cake to cool completely, about 2 hours.
ADD THE GLAZE:
Place the chocolate chips in a heatproof bowl. Heat the cream in a small saucepan until simmering, then pour over the chocolate chips. Allow to sit for 5 minutes, then stir until smooth. Drizzle the glaze over the cooled cake.
ADD THE TOPPINGS:
Drizzle the caramel over the cake, sprinkle on the chocolate chips, toffee pieces and chopped candy bar. Store loosely covered at room temperature.