I've done some testing, breath weapons don't seem at all to work. as the above post, they catch fire or paralyze themselves. my only idea is to make a potion that explodes on impact.
terrible as before, i cant make anything that jsut breaks on impact D: nothing works like a grenade, all i can really do is let out a huge PWOOMP that covers everyone around them.
There is hope!
Fireballs at least are safe to use (Well, for the caster. Not necessarily for his friends though...) and solid globs can be launched, which despite not necessarily inflicting their attached syndrome (unless it instantly vaporizes into a gas after launch) will deal some serious damage to bones and organs.
There is also the option of using one interaction to directly trigger another in the target, which doesn't require any material transmission and works exactly like a mummy's curse. I used this for a lightning spell, as it seemed both appropriate given the properties of electricity and a safe means of delivery for such a dangerous thing.
Here's the interactions for that:
...Syndrome from which ability is gained goes here...
[CE_CAN_DO_INTERACTION:START:0]
[CDI:ADV_NAME:Cast Lightning]
[CDI:INTERACTION:LIGHTNING_STRIKE]
[CDI:TARGET:C:LINE_OF_SIGHT]
[CDI:TARGET_RANGE:A:10]
[CDI:USAGE_HINT:ATTACK]
[CDI:BP_REQUIRED:BY_TYPE:GRASP]
[CDI:VERB:cast lightning from your fingertips:casts lightning:NA]
[CDI:MAX_TARGET_NUMBER:C:1]
[CDI:TARGET_VERB:are struck by lightning:is struck by lightning]
[CDI:WAIT_PERIOD:50]
[INTERACTION:LIGHTNING_STRIKE]
[I_TARGET:A:CREATURE]
[IT_LOCATION:CONTEXT_CREATURE]
[IT_CANNOT_TARGET_IF_ALREADY_AFFECTED]
[IT_MANUAL_INPUT:victim]
[I_EFFECT:ADD_SYNDROME]
[IE_TARGET:A]
[IE_IMMEDIATE]
[SYNDROME]
[SYN_NAME:struck by lightning]
[SYN_AFFECTED_CLASS:GENERAL_POISON]
[SYN_IMMUNE_CLASS:LIGHTNING_IMMUNE]
[SYN_CONTACT]
[CE_UNCONSCIOUSNESS:SEV:100:PROB:100:RESISTABLE:SIZE_DILUTES:START:0:PEAK:0:END:10]
[CE_NUMBNESS:SEV:100:PROB:100:RESISTABLE:SIZE_DILUTES:START:0:PEAK:0:END:25]
[CE_PARALYSIS:SEV:100:PROB:100:MUSCULAR_ONLY:SIZE_DILUTES:START:0:PEAK:1:END:5]
This can be used in conjunction with an ingested syndrome from a manufactured food that gives the ability to the consumer. It doesn't do any sort of permanent damage, but instantly knocks the target out, which wears off soon enough. Extremely effective when dealing with a group, because even after they wake up they are numbed for a period.
You might want to put an end timer on the caster's interaction though. I used it in a learnable secret that never ends, whereas a potion would normally be a temporary thing.
Also, the Zess could be implemented through an interaction that causes them to permanently become a form of were-creature. I bet there's a way to get it to target each race individually and apply an appropriate zess were-creature.