Pre-heat oven to 350F.
Combine white cake mix, 1 cup water, 3 egg whites and vegetable oil in a large bowl.
Whisk together until smooth.
Pour into a 8 inch prepared cake pan.
Bake for 25-30 minute or until done.
Remove from oven and let cool.
Leave as one layer or cut into 3 layers.
Add butter and shortening to bowl of mixer. Beat together until smooth.
Mix in vanilla and powdered sugar until combined and smooth.
Add 1/4 cup water and whip on high for 3-5 minutes until fluffy. Add more water 1 tablespoon at a time if needed.
Frost cooled cake with a thin layer of white frosting.
Fill a piping bag that’s been fitted with a large star tip with the rest of the frosting.
Pipe swirls all over the cake.
For the blood splatter, you can either splatter the entire cake or splatter each slice once it is cut.
Use clean hands or a new toothbrush to dip into red food coloring and flick onto the cake.
If using your hands for the blood splatter you may want to wear food safe gloves or your fingers will be colored red.