Place the eggs in a saucepan, cover with cold water, and bring to a boil over medium-high heat. Once boiling, turn off the heat, cover, and let sit for 10 minutes. Carefully drain the hot water and run cold water over the eggs to stop the cooking. Gently peel the eggs once cool enough to handle.
Slice each peeled egg in half lengthwise and carefully remove the yolks into a mixing bowl. Use a fork to mash the yolks until smooth and no lumps remain.
Add mayonnaise and mustard to the mashed yolks and stir until the mixture is creamy and well combined. Drop in a small amount of red food coloring and mix until the filling turns blood-red. Adjust the color by adding more drops if needed.
Use a piping bag fitted with a small round tip to pipe the red yolk mixture back into the egg white halves, filling them generously to mimic a rounded eyeball.
Place a small piece of crushed cookie or cracker atop the yolk in each egg to mimic the sclera's textured look. Use tweezers or a toothpick for precision if needed.
Cut a small slice from a black olive or use a tiny black candy button to create the pupil. Position it onto the yolk to look like an iris with tweezers or toothpick for control.
Add tiny red dots around the yolk to resemble blood vessels, either with a toothpick or the tip of a small paintbrush, to enhance the creepy effect.
Repeat the process for all egg halves, carefully arranging the details to create realistic, spooky eyeballs with a bloodshot effect.
Chill the assembled eyeballs in the refrigerator for 15-20 minutes to set the colors and ensure they are firm before serving.
Serve these creepy eyeballs chilled on a platter, perfect as a spooky Halloween appetizer that’s both fun and tasty.
