To make any character cake: find a simple coloring page of your character, and scale it so it will fit on top of your cake. Cut a piece of wax paper to the same size and place it over the top of your picture, so you can see it through the wax paper. Tape the picture and wax paper together by the corners onto the backside of a cookie sheet. Melt 1/2 to 1 cup of chocolate chips (depending on how big your picture is) by microwaving them in 15 second intervals and stirring between each interval in a microwave safe bowl. Transfer the melted chocolate to a piping bag or zip-top sandwich bag, and cut a tiny hole in one corner. Do a test pipe to make sure that the resulting line is the same width as the lines in your coloring page picture. Trace the coloring page picture, so you have a complete outline. Place the cookie sheet in the freezer. While the outline hardens, microwave 2 cups white chocolate chips or candy melts until melted, following the same 15 second interval procedure. Divide into bowls and dye with gel or powdered food dye (avoid liquid food dye, as water will curdle your chocolate and ruin it) so that you have all the colors you need to make the picture. You won't need as much as you think, as you are going to fill in each with just a thin layer of chocolate. The side touching the wax paper will be "up" as the display side, so it doesn't matter if it looks bumpy or messy on the top as you're piping in the colors. Place each colored chocolate in a piping bag or zip top bag and cut a small hole. Remove the outline from the freezer and fill in the picture with the colors. You can use the tip of the bag to sort of drag the chocolate around so you get a pretty thin layer. Do things like eyes and other details first, so then the layer you put down for the skin can go over the top of it (since the up-side will be down once you put it on the cake). Place your picture back in the freezer to harden for 5-10 minutes. Quickly peel off the wax paper, and press it into the cake, so that the side that was against the wax paper is up. Do it fast, because the heat from your fingers will begin to melt the chocolate. My kids love to eat their chocolate character, so when you go to serve the cake, pull the character off the top and place it on their plate, then slice the cake and serve.