Preheat the oven to 350℉. Thoroughly grease the lamb mold, dust with flour, and set aside in a cooler spot in the kitchen.
Whisk together the cake mix, oil, eggs, and water until smooth.
Place the bottom half of the lamb mold (the side with the lamb's face and without the vent hole) on a baking sheet. Pour the mixture into the bottom pan of the mold, place the top half on top and secure the mold. This can be done with baker's twine or by placing a 9x13 baking dish upside-down over top.
Bake the lamb cake for 40-50 minutes until a toothpick comes out clean. Remove it from the oven and allow it to cool for 15 minutes before gently removing the top half of the mold. Run a knife around the flat edges of the bottom half and slowly release the lamb.
Let the cake cool completely before decorating with powdered sugar or frosting.