Volcano cake for my son's 7th birthday. Bundt cake topped with smaller 6inch cake with hole cut in middle..tall narrow bottle inserted in hole filled with water..later put dry ice inside so volanco would smoke. Icing is grey..tinted some red/orange/yellow for lava. Found it looked better to frost lava then use my finger dipped in liquid food coloring to blend and give a cooler color effect. Before icing I shapped the top and side with knife to give it more a angled look.