Prepare and bake cake mix according to package directions for cupcakes.
Make the icing mix and ice the cakes when cool, reserving 1/4 of the mix.
Fill a pastry bag, fitted with a plain tip, with remaining icing. Draw a cross or R.I.P. on each biscuit. Stand a decorated biscuit on top of each cake so that it looks like a gravestone. Place the cakes on a large tray that has been covered with green paper. Place paper ghosts and bats randomly through the graveyard. Serve!