I don't know *why* they work, but the following spells will work when assigned to a monster in a mod using the "#weapon" attribute(s). I found them through random experimentation. They appear to be case-insensitive, and not all work quite as expected.
- eyeloss
- banish to inferno
- false fetters
- enslave mind (effect equals death, not enslave)
- paralyze
- astral fetters
- killing light
- weakness
The following spells/ effects DO NOT work as a weapon:
- Fanatacism
- Hellbind Heart
- Frozen Heart
- Confusion
- Numbness
- Charm
- Seeking Arrow
- Beckoning
- Freezing Touch
Frustratingly, I got "Enslave Mind" to work (and work correctly) in some combination on my first try, but lost it, and haven't been able to come up with the right combination or weapon name to make it work since. Frustrating, because the Pretender mod I'm working on could *really* use an inherent charm ability.