Mix cake as directed. Make one 9 inch round cake and bake 2 halves in round bowl.
Cut some off cake so i fits and makes a round ball. Use frosting or your preferred filler to fuse both sides of cake together.
Frost round cake a brown or pale color to be sand or dirt. You can add crumbled cookie crumbs on top of cake if you wish.
Put round cake onto planter bottom. Use a piping bag to make stems of cactus plant.
Add raw spagehtti noodles into cake for spikes.
Put cactus cake on top of round cake.
Add flower to top of cactus cake and cookie crumbles around bottom.