• Preheat oven to 350° F.

  Spray 4 6-inch cake pans with cooking spray. Cut parchment paper into 4, 6-inch rounds and add them into the bottom of each cake pan. Spray parchment with cooking spray and set aside.
• Mix cake mix, lime gelatin, and salt in a large bowl. Add eggs, oil, lime juice and coconut milk and beat for about 2 minutes. Add 1 cup of batter to each pan and bake for approximately 17-20 minutes. Cool for 10 minutes and then remove cakes from pan and allow to cool completely on a wire rack.

Lime Buttercream Frosting

• Add room temperature butter, powdered sugar, salt, lime zest and juice to a large bowl and beat until smooth. Add more lime juice if too dry or add a little more powdered sugar if too wet.

  To get a neon green frosting, add the lemon yellow food coloring and beat until fully incorporated. Next add in green a few drops at a time and beat until the desired color is reached. Transfer frosting to a piping bag and set aside.

Mutant Spider Garnishes (Make ahead)

• Add the yellow and green melting chocolate in a microwave safe dish and melt according to package directions. Spoon melting chocolate into brain molds and coat all sides. Refrigerate 20 minutes until set and remove from molds.

  Note: I chose to leave these brains hollow as a chocolate garnish but you could easily fill the brains with jam or cookie dough and seal them with more melting chocolate for an extra special dessert layer.
• Roll small amounts of fondant into thin ropes and shape into spider legs and place on a parchment lined cookie sheet, pinch to join them where they meet. Make 8 sets of spider legs.

  Roll a small amount of fondant into a ball and then press it into the bird skull mold and gently peel the mold away from the bird skull. Place on parchment paper to dry with the spider legs.

  Note: I dusted the outside of the brains and the skulls with a little bit of cocoa powder to age them a bit but this step is optional.

Assembly

• Pipe frosting onto each layer and top with the next cake layer. Pipe a thin layer of frosting to the outside and smooth out to create a crumb coat. Chill in fridge for about 10 minutes. Pipe more frosting on out side and smooth out to cover all the cake. Chill to set the frosting.
• Melt marshmallows in a microwave for about 10 seconds. Careful it will be hot. Pull melted marshmallow into strings and coat the outside of the cake.

  Ball cotton candy into a large spider egg and and top cake. Garnish with spiders attaching with extra frosting as needed. Allow cake to come to room temperature and serve. Enjoy!