Step 1: Preheat your oven to 350°F (175°C) and grease two 8-inch round cake pans.
Step 2: In a large bowl, sift together the flour, sugar, baking soda, salt, and cocoa powder.
Step 3: In another bowl, whisk together the buttermilk, eggs, oil, vinegar, vanilla, and red food coloring.
Step 4: Gradually add the dry ingredients to the wet ingredients, mixing until just combined and smooth.
Step 5: Divide the batter evenly between the prepared pans and bake for 30-35 minutes or until a toothpick comes out clean.
Step 6: While the cakes cool, beat the cream cheese and butter together, then gradually add powdered sugar to make the frosting.
Step 7: Frost the cooled cake layers with a crumb coat, chill for 30 minutes, and then apply a final smooth layer of frosting.
Step 8: Prepare the blood drip by melting white chocolate chips with heavy cream, then stir in red gel coloring.
Step 9: Carefully pour the red ganache around the edges of the cake to create the 'blood drip' effect, then fill in the top.
Step 10: Chill the cake for at least 1 hour before serving to set the drip.