For my skull cake, I used devils food cake in a 2 piece skull pan. Lightly frosted with butter cream and let dry. Then heavier frosted again with butter cream. I used paint brushes to frost in the smaller areas. To draw in the teeth I thinned the frosting with water and used a toothpick to outline. I used a paintbrush to paint in the missing teeth.
I piped green leaves all around the cake for a border and then placed the skull on a platter. I surrounded the platter and skull with different types of gummy worms and bore a hole in one of the eye sockets for the gummy worm to hang out.