Sometimes, a couple of marzipan mice just won't cut it -- you want your cake to be really dramatic. For example, once you've carved and iced a cake to look like Mount Vesuvius, an erupting chocolate lava flow will make it a memorable volcano. Cake artists have used everything from dry ice to electronic devices to give their cakes extra flair.
There are two things to keep in mind if you decide to unleash your inner mad scientist on your next cake. The first is that you'll usually want to have a big reveal: Time your effects carefully to make the biggest impact. The second is that your decorations might be inedible or even dangerous if eaten. If you're lighting your cake with light-emitting diodes (LEDs), for example, you'll have to take the decorations off before serving and keep the battery well away from the rest of the cake.