I’ll start with a short foreword. Werebeasts and vampires are both originally created as people cursed by na angry god. So their state is a kind of punishment.
That could be true in the case of werebeasts, the confused and scared peasants turning into a ravaging beast and killing their own beloved ones. However, vampires lose all human traits while changing – they become thirsty and cunning corpses, living forever and with enough strength and intelligence to protect their lives when things get ugly. Apparently, they are also not haunted by their conscience and kill without remorse. That is not an curse. Could be for the relatices, but not for the vampire. This a kind of dark and perverted bless, not a punishment.
And I’d like to see a divine wrath having its way to ruin any heretic, so I present you a sludge curse:
Being caused by a divine curse or a syndrome transmitted by sludges themselves, the sludge curse will start a slimification process in an affected body part (similar to decay), turning it into an ooze. As the creature is transformed, its body will become a shambling mass of semi-translucent ooze, with a skeleton made of slimebone (a bone material harder than normal bone) and no organs left. It becomes immortal, it will gain extravision, it does not need to eat, drink, breath or sleep anymore, it does not feel fatigue and cannot fall unconscious and it cannot speak as it has no mouth.
The FUN part is that the ooze its body is composed of causes the slimification syndrome that can turn any creature touching it into another sludge. One touch is enough. Your dwarven doctors can wash it off with a soap, but sludges leave trail of ooze on the ground as they move (always wear boots), they can spit it (don’t forget your shield), any weapon that strikes them becomes coated in the ooze (well…) and if they have no weapon in hand, they will try to wrestle any opponent, infecting them.
Also, for it to be a real curse, sludges remain fully sane and aware of their condition. This is especially important in Fortress Mode, as your infected dwarves will try to continue their daily tasks, doing their jobs, trying to eat, drink, chat with friends or sleep. But they cannot eat nor drink nor speak nor sleep. All other dwarves are frightened and threatened by them, runing away or attacking in case of military. They can feel pain from their wounds but cannot fall unconscious and are nearly indestructible. And they gain a number of bad thought from their condition alone, so any sludge dwarf (or sludge anything) will sooner or later drop into insanity. You should rather dispose of them, or they’ll try to drown themselves in your well and contaminte your water in the process.
You ask how to get these abomination into your fortress? Well, if any kind of religion is ever added, it could be a nice punishment for not performing the right rituals. For the time being, they can be generated during the worldgen and either wander aimlessly or be walled up in a tomb alive and then excavated by an unaware adventurer. And the goblins could take along some caged sludges during their seiges, releasing them on your military.
That is how I imagine a curse! Now you know why to fear the gods.
Any thoughts?