To hard boil the eggs, bring a pot of water to a boil.
Add 2 tsp. baking soda, optional, to make the eggs easier to peel.
Add the eggs, and boil for 11 minutes.
Remove the eggs to an ice water bath to stop the cooking.
Peel the eggs, and cut them in half, scooping out the yolk into a separate mixing bowl.
Once all of the eggs are prepared, take a fork and mash the egg yolks in the mixing bowl.
Add the mayonnaise, mustard, and relish to the bowl of egg yolks.
Add salt and pepper, to taste.
Add the yolk mixture to a piping bag, and pipe back into the egg halves.
To make the spiders, take 6 black olives and cut in half.
Place each half onto the center of the deviled egg.
Make the legs by carefully slicing additional black olives, and then quartering each slice into 4 legs.
Chill the finished eggs in the refrigerator until ready to serve.