Preheat oven to 350°F. Line cupcake pan with liners.
In a large bowl, whisk together the eggs, butter, milk, and yogurt until pale and creamy. Slowly pour in the mix and blend until smooth, about 1-2 minutes. Pour the batter into each cupcake tin, about 2/3 full. Bake on 350°F for 20-25 minutes until lightly golden.
While the cupcakes bake, make the edible blood. Whisk together the powdered sugar, water, red food dye, and cocoa powder in a small bowl. Blend until smooth and thick. Set aside.
Remove cupcakes from the oven and allow them to cool for about 15-20 minutes. Prepare the vanilla frosting while cupcakes cool. Cream one stick of butter with an electric mixer until pale yellow. Add in the vanilla frosting mix and milk, and blend until smooth and fluffy.
Pipe the frosting onto cupcakes. Use a syringe to make two vampire teeth marks and fill the cupcakes with the edible blood. Drizzle extra blood droplets on top for desired effect and add any spooky accessories. Enjoy!