Chocolate gummy worms? Doesn't that sound a little wierd? Why don't you make worms and dirt instead? (chocolate putting layered with chocolate crumbs and topped with gummy worms of whatever colour you desire - they come in multi-colours too!)
Hey, did you know I've only ONE cooking contest and I won it with the above idea, I made it in a sand bucket and add fake flowers too...did you know it was beautiful??