Preheat oven to 350 degrees.
Lightly grease a 9x13-baking dish.
Combine the cake mix, vanilla pudding mix, pumpkin, water, oil, eggs, and pie spice in a large mixing bowl; pour into the prepared dish.
Bake in the preheated oven for 45 to 50 minutes.
Allow cooling to room temperature on a wire rack.
Cut the cake into 1-inch cubes.
Whisk together the milk and cheesecake pudding mix.
Allow setting, about 2 minutes.
Fold the whipped topping into the pudding mixture.
Layer 1/3 of the cake cubes into the bottom of a large bowl; top with 1/3 of the cream mixture and sprinkle with 1/3 of the pecans and toffee bit.
Repeat layering until all ingredients are uses.
Refrigerate 1 hour before serving.
Ready in 3 hours 10 min.