Preheat your oven to 350°F (175°C) and line a 12-cup muffin tin with Halloween-themed paper liners.

In a large mixing bowl, cream together the softened unsalted butter and granulated sugar for 2-3 minutes until light and fluffy.

Beat in the eggs one at a time, then mix in the vanilla extract and gel-based red food coloring until smooth.

In a separate bowl, whisk together the all-purpose flour, cocoa powder, and salt.

Gradually add the dry ingredients to the butter mixture, alternating with the buttermilk.

Divide the batter evenly among the muffin cups, filling each about two-thirds full, and bake for 18-20 minutes.

Mix together the red velvet cake crumbs, sweetened condensed milk, melted butter, and an extra drop of red food coloring until smooth.

Once the cupcakes are cool, core the center of each and fill with the prepared filling.

Beat the softened butter until creamy, then gradually add powdered sugar, milk, and vanilla extract to make frosting.

Color the buttercream frosting with ivory or peach food coloring and frost the cupcakes.

Decorate with candy fangs and drizzle with red syrup or gel to create bloody bite marks.