Preheat the oven to 180°C (160°C for fan forced). Grease and line 3 cake tins with baking paper.
Beat the cake mix, eggs, oil and water in a large bowl with electric mixer on low speed for 30 seconds. Beat on medium speed for 2 minutes until smooth and creamy. (Do not eat batter as it contains raw eggs.)
Pour the cake mixture evenly between the 3 cake tins.
Bake in the centre of the oven for 15 to 20 minutes or until a skewer inserted into the centre of the cake comes out clean. Leave in the cake tins for 10 minutes. Remove from the tins and place on a cooling rack. Peel off the baking paper. Cool completely, approximately 1 hour.
Place the first cake layer onto serving platter. Spread 1/3 of the tub of frosting over the top. Place the second cake layer on top of the first; spread 1/3 of the tub of frosting over top of the cake. Place the final cake layer on top. Frost the top and sides of the cake with a thin layer of frosting to cover completely. Place in refrigerator for 30 minutes to harden.
Remove 50g of frosting from the second tub. Place in small plastic food-storage bag; set aside. Remove the frosted cake from the refrigerator, and spread a thick coat of frosting on top and sides of cake. Return cake to refrigerator for 30 minutes to harden.
Microwave the candy melts in a small bowl according to package instructions; stir until smooth. Holding the pretzel rod or breadstick on one end, spread melted candy melts to cover 3/4 of the rod on all sides. Place the rod on a piece of baking or wax paper and sprinkle 2 tablespoons of sprinkles or stars to cover. Allow to sit for 15 minutes or until sprinkles are attached to the rod.
Microwave the dark chocolate melts and cream in a small bowl for 30 to 40 seconds; stir. Continue to microwave in 5-second intervals until chocolate has melted; stir until smooth. Allow to stand for 10 to 15 minutes or until the chocolate has cooled and mounds slightly when dropped from a spoon.
Remove the frosted cake from refrigerator and place on a cooling rack with baking or waxed paper under the rack. Pour the chocolate cream mixture onto the top centre of cooled frosted cake; spread to the edge allowing some to drip down the side.
Place the sprinkle-covered rod off centre on top of the cake and push into the cake slightly so that it is at an angle. Take the reserved frosting in the bag, cut off bottom corner of the bag, and pipe around the rod going upwards to form a large mound around the base. Cover the mound and top of the cake with candy sprinkles and stars.
Press 2 candy-coated chocolate beans on the sides of the cake. Use the icing pen to make a small circle in the centre of each chocolate bean to create an “eye”. Place 6 slivered almonds around the two eyes to look like claws. Repeat with remaining beans and almonds around the side of the cake. Return to refrigerator for 30 minutes to harden.
Decorate the small brown bag as desired and place on top of the sprinkle-covered rod. Use a piece of crumpled aluminum foil to fill inside of bag to maintain shape if needed. Store covered at room temperature; remove the rod when covering the cake for storage.