Chocolate Haunted House Cake

Heat oven to 350 degrees F.
Grease and flour one 10-inch, one 8-inch, one 6-inch and one 250-mL ramekin; cover bottoms with parchment.
Prepare cake batter as directed on package, blending in dry pudding mix into batter before pouring into prepared pans.
Bake, rotating pans halfway, until toothpicks inserted in centres come out clean, testing every 10 min.
and removing the smallest cake first (total bake time will 35 to 40 min.).
Cool cakes in pans 10 min.
Invert cakes onto wire racks; gently remove pans and parchment paper.
Cool cakes completely.
Meanwhile, melt chocolate as directed on package.
Beat butter in large bowl with mixer until blended.
Add melted chocolate.
Gradually add icing sugar and milk, mixing on low until smooth.
Stack cake layers from largest to smallest.
Secure each layer to one another by lifting four corners of each layer and dabbing a small amount of chocolate icing underneath.
Frost top and side of cakes with chocolate icing.
Use green icing to frost each sugar cone.
Place each Swiss cake roll on cake using the photo as a guide.
Place frosted sugar cones on top of each roll.
Create stars and cobwebs on cake using white decorating icing.
Decorate edge of each cake layer with pearl sprinkles.
Add gummy candy bats and place wafer cookies at the front of the bottom layer of cake.