Break the white chocolate bar into squares for tombstones. Break off a few with jagged edges to look like old stones.
Place black icing or melted chocolate into a plastic zip-tip bag and cut a tiny hole in the corner. Pipe 'RIP' onto the chocolate squares. Allow to dry. (You can place them in the refrigerator for a few minutes for a quick dry.)
Sprinkle grass over top of cake. Insert pieces of white chocolate to make tombstones.