THE KEEPERS OF NERGAL
There's an interesting use of sorcery in
The Spider-God's Bride adventure one,
The Necromancer's Knife. I've tweaked this a bit for my game.
The Keepers are priests of Nergal. They keep and maintain the dead that are in the crypt below the city. When someone is killed on the streets, the dead are left where they fall. That is the custom. For, at dusk, a thick cloud of fog will roll into the city and cover where the dead lay. If anyone looks close (and most lock themselves inside a safe place, as far away from the Keeper's Fog as they can get), that person will probably see vague movement of what looks like dead people moving inside the fog. The dead have come to claim the newly dead, taking them into their new existence. Any who actually see the fog and/or the shapes moving within are subject to the Terror Check from the core rulebook.
What's really happening (and this is a GM secret that the players may or may not discover) is that those moving in the fog are quite alive. They are men. Priests of Nergal who have asked for and gained a blessing from their god (they cast a sorcerous spell, though they don't think it as sorcery). Specifically, they are using a version of the Prestidigitation (Conjuring) spell to create the illusion that the priests are walking dead in a cloud of sorcerous fog.
The priests, called "The Keepers", under cover of this spell, come in a group, pick up the dead, and take them under ground to the Crypts of Nergal.
Prestidigitation (Conjuring): The specifics of this particular spell, since the spell can be tuned to react in a number of outcomes, is that the Priests of Nergal only know this specific use, and they look at the outcome as a combination of religious faith, specific dogma, and a blessing from Nergal.
The fog is created through alchemy. A fairly easy to create (but with secret ingredients only known to The Keepers) liquid that is poured on the ground. The substance immediately begins to bubble, foam, and create fog.
Once the fog is dense enough, and a large enough cloud is created to encompass the required number of Keepers, the spell is cast in the manner of a blessing (verbal component, with casting time as one standard action). The spell requires 2 power points be spent, one for each effect. The fog is moved as per the spell, surrounding the Keepers. And, each Keeper casts the spell individually to give himself the appearance of walking dead. Those Keepers not controlling the fog spend only 1 power point to their appearance.