Preheat oven to 350 degrees
Sprinkle cocoa powder into the skulls in cake pan
Pour cake mix into a medium bowl.
Add milk, vegetable oil and eggs to cake mix. Whisk well to combine.
Pour mixture into skull pan until each skull is about 2/3 full.
Cook for 14 minutes. Test by inserting a toothpick and making sure the toothpick comes out clean.
Let sit for a few minutes to cool and then transfer to wire rack.
Repeat until all batter has been used.
If you want to icing/decorate the skulls, place skulls in fridge for 15-20 minutes so the cake cools down.
Decorate however you wish. Cool in fridge so icing sets and serve with a glass of milk! Enjoy!