Erik Tenkar mentioned something in passing that really struck me. It may not be new to you, but the idea that a creature that appears undead is merely cursed is brilliant.
One example I can find in the various Swords & Wizardry books is the Omgoth. They eat like ghouls, look like ghouls, and hang around other ghouls. Yet, they are not undead. It even says in the creature description that Omgoths cannot be turned.
I’ve used a similar idea for years for lesser undead. Skeletons and zombies are not undead, but merely animated corpses. The abilities and immunities of an animated object are remarkably similar to undead. It may not be effective at higher levels, but to a low-level party, it is really freaky when the Cleric’s Big Magic Trick has no effect.
What do you mean I don’t roll to turn them, they’re skeletons!
I already do not consider shadows and ghosts as undead, so anyone that has played in a game I run will know that. However, the thing that never occurred to me was to have a cursed creature that looks and acts like a vampire, but is not a vampire. They can even take damage from daylight as part of the curse. How about a cursed lich? A powerful magic-user cursed to endlessly research the same spell in the vain hope of reversing the curse. Then there’s new creatures like the phasma from the Pathfinder SRD. In many ways, it is a cursed Cleric. Considering that the Cleric’s god did not save him/her from the curse, I almost think that releasing the curse is worse.
There used to be a blog at Monstrous Television that mentioned abdead as creature similar to undead, but not affected by Cleric in the same way. I wish that archive.org could bring back this post. Essentially, abdead skeletons are intelligent and not able to be turned. I can’t remember the rest of the idea except to say that it was great.
Still, there’s more to reskinning undead that removing the Cleric’s Big Magic Trick. I moved traditional incoporeal undead into a new category of creature. In my games, these ghosts (including specters and shadows) can be battled by psionic characters. Whereas the Cleric takes out the undead and horrible amalgams of bone, sinew, and rot, the Psionicist battles the vengeful spirits of mortals that cannot leave this plane with unfinished business.
That’s my two cents on reskinning undead. Have you ever reskinned undead creatures?