Follow these steps to create your Bloody Eyeball Deviled Eggs:

1. Boil the Eggs: Place the eggs in a pot and cover them with water. Bring to a boil over medium-high heat. Once boiling, remove from heat, cover, and let sit for 12 minutes.
2. Cool the Eggs: Transfer the eggs to an ice bath or cold water to cool completely for about 10 minutes. This will make peeling easier.
3. Peel and Halve the Eggs: Once cooled, peel the eggs and cut them in half lengthwise.
4. Prepare the Filling: Remove yolks and place them in a mixing bowl. Add mayonnaise, Dijon mustard, apple cider vinegar, salt, and pepper to taste. Mash until smooth and well combined.
5. Add Food Coloring: Add a few drops of red food coloring to the yolk mixture to give it a “bloody” appearance. Mix until you achieve your desired color.
6. Fill the Egg Whites: Spoon or pipe the yolk mixture back into the egg whites.
7. Create Eyeballs: Slice the black olives in half and place one half on each deviled egg, cut side up, to resemble pupils.
8. Add Extra “Blood” Effect: Drizzle some additional red food coloring around the edges of the deviled eggs to mimic blood.
9. Garnish (Optional): Sprinkle with fresh parsley or paprika for an extra touch of color or garnish.

Now, your Bloody Eyeball Deviled Eggs are ready to scare and delight your guests!