In the midst of some discussion in ##crawl, I got to thinking that it would be neat for ghouls to gain additional utility from the spell Corpse Rot.
Specifically, the spell could consume a portion of the ghoul's body as it would a monster's corpse, thus allowing the user to run around leaving a miasma trail like a rotting devil. It could have great usefulness as an escape spell, but would come at the cost of (significant) rot. While ghouls can restore rotting very simply, the prospect of suffering large rot in a combat situation should be enough to make the user think twice.
Theoretically, the spell would also effect vampires and mummies in the same way, though balancing becomes an issue when these other races get involved. It's my understanding that vampires restore rot by drinking from corpses, so they aren't too much of an issue. Mummies, however, are problematic, as their rot is difficult to restore until they gain their special magical infusion thingy. With the help of a little hand-waving, however, it could be resolved: mummies are too desiccated for the spell to consume their bodies. Alternatively, the spell could cause less rot (and thus have less potent an effect) when consuming mummy flesh -- or vampire flesh, for that matter.
However, this FR is intended just for ghouls (it would be neat for GhNe to have a flavorful trick up its sleeve, if ghouls had sleeves), so I'd be happy to find some way of rationalizing it as a ghoul-specific effect. If we absolutely must allow it for Vp and Mu, it should be less potent for them. Besides, Vp and Mu already make good necromancers as it is.
Anyway, thoughts and opinions are appreciated.
-Mong
Another possibility is for the spell to give a brief poison/rotting unarmed attack for ghouls, at the cost of accelerated decomposition during the spell.
Since the process of mummification is all about making rotting impossible, and in-game mummies ignoring all sources of rotting (save for mutation decomposition, which works using a different mechanics), what about simply not making Corpse Rot affect mummies -- both positively and negatively.
@castamir: Yes, I had been thinking about something like that as well. Embalming would of course render decomposition impossible (or nearly so). That would both make logical sense and help with balance.
@nobody: This sounds like a good idea too -- ghouls are natural unarmed fighters, so it would be neat to have a way of buffing that. Now I'm torn between augmenting hand-to-hand damage and providing an escape spell. :)
-Mong