Preheat your oven to 350°F (175°C) and line a 12-cup muffin tin with paper liners. In a large mixing bowl, cream together the softened butter and sugar until light and fluffy, about 2-3 minutes. Add the eggs one at a time, beating well after each addition. Mix in the vanilla extract and red food coloring.

In a separate bowl, whisk together the flour, cocoa powder, and salt. Gradually add the dry ingredients to the wet mixture, alternating with the buttermilk, until just combined. Stir in the baking soda and vinegar mixture. Spoon the batter into the prepared muffin tin, filling each cup about 2/3 full. Bake for 18-20 minutes, or until a toothpick inserted comes out clean. Let cool in the pan for 5 minutes before transferring to a wire rack.

In a small bowl, combine the red velvet cake crumbs with the sweetened condensed milk and melted butter. Add red food coloring to achieve a vibrant red filling. The mixture should be smooth and slightly glossy.

Once the cupcakes are completely cool, use a small knife or cupcake corer to remove a small section from the center of each cupcake. Fill each hole with the creamy red velvet filling.

In a large bowl, beat the softened butter until creamy. Gradually add the powdered sugar, one cup at a time. Add the vanilla extract and 2 tablespoons of milk or cream, beating until smooth and fluffy. Add food coloring to achieve a pale skin-tone color.

Frost each cupcake with the pale buttercream using an offset spatula or piping bag, ensuring a smooth surface.

Use candy fangs or red gelatin drops to create puncture marks on the cupcakes. Drizzle red syrup or edible gel from the puncture marks to create 'blood' drips.

Arrange the decorated cupcakes on a serving platter, surrounding them with additional red syrup drips.