I made this Halloween Graveyard Cake for a Halloween party at work. It is entirely edible. The zombie/tombstone is made from modeling chocolate, painted with icing colors/alcohol. The top is cookie crumbs for dirt and buttercream grass.
The sides are modeling chocolate sponge painted with blue/green/white with gray buttercream for mortar. The spikes are pretzel sticks covered with buttercream (black buttercream with a star tip).