In the bowl of a stand mixer, combine the cake mix, water, oil and eggs. Mix well, scraping the sides often.
Spray or line a 13x9 baking dish. Pour the cake batter into the baking dish and spread evenly.
Bake in the preheated oven for 28-30 minutes or until golden brown and set in the center.
Allow to cool completely.
Crumble the cake and add 1 cup of premade vanilla icing. Mix in a bowl of a stand mixer with the paddle attachment just until combined.
Use a cookie scoop or tablespoon, to scoop out the batter and shape into balls. Place on a sheet of parchment and repeat. Chill in the fridge or freezer until ready to decorate.
Melt the white candy melts in a microwave safe bowl until smooth.
Using a spoon, dip each cake ball into the melted white candy melts. Tap the excess on the side of the bowl and place back on the parchment. Repeat.
Once the white candy melts have set, they can be decorated.
Melt the black candy melts in a microwave safe bowl until smooth. Transfer to a piping bag and cut a small hole in the end.
Carefully pipe a small head, bigger body and eight legs for each spider on the top of each cake ball. Allow to set.
Notes
Storage: Cake balls should be stored in an airtight container in the fridge for up to 1 week.