Step 1: Ingredients
1 tsp (or more) vegetable seasoning
a few tbsps of miracle whip or mayonnaise
red, black and green icing color (it's thicker than normal food color and has some sugar in it, but the sugar won't really be noticeable)
1 tbsp paprika
red pepper (for decoration)
I included sesame and poppy seeds in the picture because they would make nice rocks/gravel/other creepy Halloweenish decorations, but I decided not to use them.
If you can get vegetable seasoning from Market SpiceMarket Spice (based in Seattle) do it. It's really exceptionally tasty, and is the best thing ever to replace salt on french fries.
Step 2: Boil the Eggs
Heat the water to boiling, stirring pretty much constantly.
Boil for 15 minutes. Keep stirring them for the first 5 to 7 minutes of that. The stirring prevents the yolk from setting off-centered in the egg, which would result in a very thin side.
Pull them out of the water (using an appropriate safe method) and place them in cold water.
Once they're cooled off - 10 or 15 minutes at least - peel off the shells. The easy way to do this is to place one on a hard surface then roll it back and forth until the shell cracks. Peel it from there - the shell should pretty much hold together. Do this to all of them (obviously).
Rinse them off to remove any other bits of eggshell.
Step 3: Prepare the Filling
Use a small spoon to scoop the egg yolks out and into a bowl/mixer bowl.
Once all of the yolks are in the bowl add the tsp of vegetable seasoning, a little mustard and a scoop of mayo. Mix this until the yolks are broken up and it's all distributed. Keep adding mayo until it's a nice creamy consistency. Taste it and adjust the seasoning if necessary (this is where you may want to add a little salt and pepper or more vegetable seasoning.)
If you're doing two different colors separate the filling into two bowls. Add the food color a few drops at a time until you get a nice gross color. I went with black and green, but this is a personal artistic choice. Really consider what you and your guests will find most offensive.
Step 4: Fill the Eggs
If you're not serving them right away box them and refrigerate them for a while. The food color will seep into the white of the eggs and make them look even grosser.
Step 5: Blood Splatter and Decorate
I cut a strip of red pepper about half an inch wide then cut it down into little devil horns, tombstones and crosses. I placed them on the filling so they would stick in place well.
Place 1 tbsp of paprika in a bowl. Add a few drops of red icing color. Then add a little water and mix. You're looking for the consistency of thick blood. Adding a little cornstarch can help thicken it up if need be. Keep tweaking it until it's just gross enough. This replaces the delicate paprika sprinkle applied to deviled eggs at formal lady's luncheons and similar affairs.
When you're ready to serve them use a spoon to spray the blood around the tray. Practice a bit on a plate first if you're worried. A knife covered in blood is also a nice decorative touch.
Serve them to your offended friends/family/guests/etc.