I made this cake for a teenager's birthday. It was chocolate cake with bananas and cream filling. I frosted the whole cake in butter cream colored grey, then I dabbed black and purple randomly on the cake with a toothpick and with my off set spatula a little wet smeared the colors into the grey to give it a different effect. I decorated the rest of the cake with plastic picks and fondant cut-outs. I also added cookie crumbs all over to make it look like dirt!