Preheat and prepare: Preheat oven to 350°F (175°C). Line 24 muffin cups with Halloween-themed or black cupcake liners.
Mix dry ingredients: In a large bowl, sift together flour, sugar, cocoa powder, baking soda, and salt. Whisk to combine evenly.
Combine wet ingredients: In another bowl, beat eggs, then add oil, buttermilk, food coloring, vanilla, and vinegar. Mix until well combined and bright red.
Make batter: Pour wet ingredients into dry ingredients. Mix until just combined - don't overmix. Batter will be thick and vibrant red.
Fill cupcake liners: Fill each liner about 2/3 full with batter. Use an ice cream scoop for even portions.
Bake: Bake for 18-20 minutes, or until toothpick inserted in center comes out clean. Don't overbake or they'll be dry.
Cool: Let cupcakes cool in pans for 5 minutes, then transfer to wire racks to cool completely before frosting.
Make frosting: Beat cream cheese and butter until light and fluffy, about 3 minutes. Gradually add powdered sugar, beating until smooth. Add vanilla. Divide and tint some orange if desired.
Decorate: Pipe or spread frosting on cooled cupcakes. Add Halloween decorations like spider rings, candy eyes, or pipe spider webs with black gel.
Serve: Display on Halloween-themed cake stand or arrange in shape of pumpkin or spider for dramatic presentation.