Melt the chocolate and make 9 discs of melted chocolate on a sheet of parchment paper.
Cut the ladyfingers in half and place on the chocolate discs. Let dry. Then, using a toothpick or a piping bag, make a cross of melted chocolate on the finger. Let dry completely.
Meanwhile, make the rice puff base. In a large saucepan over medium heat, melt the butter and the marshmallows, stirring constantly. Add in the green food coloring and stir.
Place the rice puffs in a large mixing bowl and add the green mixture. Stir to combine. Press the mixture into a lined square pan. Press flat and let cool for about 1 hour.
Remove from the pan and cut into 9 squares. Put a small amount of chocolate under each graveyard decoration and place on rice puff treat. Let dry and serve.