Prepare cake mix according to package instructions in three 6 - inch baking pans. Once baked, allow to completely cool outside of pans.
In zip lock bag crush 10 chocolate crème cookies. Set aside.
In separate bowls add 1 cup black candy chips and 1 cup red candy chips. Set aside.
In a microwaveable bowl, heat 1 cup heavy whipping cream for 1½ minutes.
Pour half the heavy cream mixture into one bowl of chips and other half into the other bowl of chips. Stir until chips are completely melted. Set aside.
After the cakes have cooled add a small amount of buttercream icing to the top of each layer spreading evenly.
Stack each cake layers on top of one another. Add thin layer of icing to entire cake and freeze 15 minutes.
In a small bowl, add 2 parts purple food coloring to 1-part black food coloring. Mix well. Ice cake with deep purple icing.
Add chocolate crème cookie crumbs, tombstones and bone candies to top of cake.