Boil the eggs: Add 6 large eggs to a pot of cold water and bring to a boil. Cook for 20 minutes, then place the eggs in cold water for 2-5 minutes. Peel them once cool.
Prep the yolks: Slice each egg in half, remove the yolks, and press them through a mesh strainer into a bowl for a smoother filling.
Make the filling: Mix 2 tbsp. mayo, 1 tbsp. spicy mustard, salt, and pepper with the yolks. Add red food dye or beet juice for a spooky red color.
Toast bread circles (if using): Cut small circles from 3 slices of bread, flatten them, and toast at 350°F (175°C) for 5-7 minutes.
Create an olive slot: Cut a small hole in the top of each egg white, insert half of the cut piece back into the egg to hold the olive in place.
Add the "eyeballs": Slice an olive and place a piece into each egg where you made the hole.
Assemble the eggs: Pipe the filling into the eggs, flip them over, and place a bread circle or rice cracker on top to seal.
Finish & serve: Carefully flip the eggs back over, ensuring the filling stays in place, and repeat for all eggs.