Something worse than undead

[NichG]

To figure it out, lets look at why undead are so squicky, and then try to outdo that. From least awful to most awful:

- Undead are constant reminders of death. They make something which most people put out of mind as an abstract fear into something concrete and everpresent. People know that they will die some day, but generally to protect themselves they don't think about that constantly - otherwise, you'd see a lot of 'well I'm going to die eventually anyways, so why do anything?' kind of depression. So undead which can be recognized as such can psychologically destabilize the living population around them.

- Undead are beings who were once someone, but after their death they're now someone else serving the purpose of the necromancer. So each corpse walking around is a reminder to the friends and family of the person who became that corpse of that person. In some sense, its stealing the impact or significance of that person's death. There are also implications of violation here - the body belongs to the dead person or their family, so the necromancer is stealing it.

- In cultures with belief in the afterlife and the soul, there's also the unsettling thought of 'is this actually a husk, or is the person's soul trapped within?'. If the undead behaves differently than the living person, but still behaves like a sentient being, there's the potential implication that the soul has been twisted or altered by the working (rather than just replaced with a different agency).

Of course, there are lots of ways to lessen the negative impact of these. Sentient undead who are hard to detect and who behave like the person behaved during life and are not under the control of their necromancer are probably the easiest to get a society to adjust to - at that point its just a form of life extension with some minor side-effects. On the other hand, shambling rotting corpses mass-animated by government mandate, and which show faint signs of recognizing people they knew in life are pretty much the worst case scenario.

So this new monster needs to do worse than destabilizing the psychology of the population, constantly reminding people of old emotional traumas and sorrows, and violating a person's body and soul.

One thought is that anything which works through people's children might work. For example, some kind of monster which essentially takes over or infects a child even before birth and as the child grows slowly turns them monstrous. For maximum degree of awful, the child should retain enough of itself just long enough to show a glimmer of the person they could have become, just before the monster inevitably takes over.

If you really want a perfect storm, have it so that killing the child and raising them as sentient undead can actually cure them.