- You can't cast on the enemy turn (I assume firing tower defenses are an exception)
It seems like every month or so someone brings that 'rule' up and fails to also take note of the many, many specific exceptions mentioned in the comic.
Basically it boils down to this, I'm pretty sure:
-Casters cannot cast spells that would negatively affect an enemy off turn. Exception:
The hex or city the caster is in currently occupied by enemy units.
This means that anything not directly harmless in nature, such as thinkagrams, message hats, moneymancy, healing, dollamancy. One might think croakamancy is indirectly harmful and thus okay, but keep in mind that since it can also target fallen enemy units, you cannot actually do it off turn in the rare situation your croakamancer finds himself with corpses off turn.
One could make a case for the exception covering mid-battle zombie making though...