Make up the cake mix according to manufacturer’s instructions, line an 8 inch cake pan with parchment circles and pan spray and deposit prepared cake mix (we used 1 pound per 8 inch pan). Bake until cake springs back lightly when touched and a toothpick inserted into the center comes out clean. Let cool completely. While the cake layers are cooling, add green food coloring to buttercreme until the icing matches the reserved granny smith apple. Mix together 1 pound 8 ounces Dawn Select Plus Chocolate Donut and Roll Icing with 1 pound corn syrup. Mix in enough black food coloring to make the mixture black.
Once the layers have cooled, use the green icing to stack, ice, and fill a three layer cake. Smooth ice and refrigerate for 20 minutes to one hour. While cake is setting up, cut two eye shapes, one small triangle, and three half inch strips out of painters tape. Place shapes on the apple in the shape of a skull. Warm black icing and carefully drizzle over apple, leaving some space open. While glaze is still warm, peel off tape. Using a piping bag, place warm glaze in it, pipe around edges of cake to create a drip look, place a little more icing on the top of the cake and spread. Place apple on top of cake for “poison apple” look.
If cutting out a skull shape seems too complicated, simple pipe the warm black icing around the crown of the apple just like the drip cake.