Preheat the oven to 350 degrees and line a baking sheet with parchment paper. In a bowl, whisk together the flour, cocoa powder, baking soda, and salt.
In a separate bowl, beat the softened butter and granulated sugar until light. Add the egg, red food coloring, and vanilla extract, then mix until combined.
Stir the dry ingredients into the wet mixture to form a dough. Scoop and shape into 8 small balls, place them on the baking sheet, and flatten slightly.
Bake for 10 to 12 minutes until the edges are set. Cool the cookies completely on a wire rack.
Beat the cream cheese and softened butter until smooth. Add the powdered sugar and vanilla extract, then mix until creamy.
Spread the cream cheese icing over each cooled cookie. Use red gel food coloring to draw veins around the edges and place a candy eyeball in the center of each one.