I know enemies thaw if you attack them, so forget freeze. I was wondering if enemies like the royal jelly can be both cursed and poisoned, or poisoned and shocked, or stunned and set on fire.
Do elemental effects 'stack'?
By the way, these are not "elemental" effects. They are status effects. Status effects have nothing to do with elemental damage in the rules of the game. In the design of the game, they often, but not always arrive together. But keeping them separate can really help avoid confusion. I'm not trying to browbeat you; I'm just trying to clear up a common misconception, in case any impressionable youngsters are reading this thread.
Bopp, you didn't answer the actual question :o
Yes, you can stack status effect (as pointer by Bopp, the name is status and not elemental). The notable exception is freeze and fire : if you freeze a mob then, of course the fire tick will break it. But if you fire a mob and then a freeze occurs, the freeze will stop the fire.
Apart from that, a mob can have all the effects you can apply at the same time. Before JK went easy mode, it was actually a very common strategy to stack curse, poison and fire (using vials) on him to shorten the fight.
And haze bombers use that property to maximize their utility using 2 haze bombs at once. Notably the fire + shock for maximal destruction (especially in RJP) and freeze + poison for maximal support (notably in FSC). Although haze bombers are kinda rare.
You can apply different status effects to the same monster. In the Royal Jelly fight, at least before the repeated nerfs, it was quite typical to start the fight by setting it on fire, curse, shock and poison... all at once.
Vapor bombers do this frequently. For example, dropping both Ash and Voltaic, or Stagger and Venom, etc.
You can drop both Ash and Shiver, but the fire and freeze will cancel each other out. What will happen is that the monster will catch on fire taking damage immediately. Then the freeze will put out the fire. But because they are standing in a Ash's vapor still they'll catch back on fire, taking damage again. This causes the fire damage to apply about 30% faster than if only Ash was dropped, but the status switching makes the monsters do really weird stuff and people can get trapped by frozen monsters, not always worth the trouble.
As for actual stacking, like poisoning then setting a monster on fire... As far as I know, it doesn't make any difference. If you poison something then set it on fire, the fire damage won't be stronger just because it is poisoned. Been a long time since I played around with such things, but that's what I recall, could be wrong.
All of the status effects may "stack" together with the exception of Freeze. Freeze will break if the victim takes damage of any sort. So the statuses that can damage, most obviously Fire and also Shock cannot coexist with it (for any useful amount of time) on the same target. Thus the rest (I'm not actually certain about Curse as I've yet to try it but Stun, Poison, Sleep: yes) may be applied all at the same time to great effect with the exceedingly rare circumstances that would allow it.
Shock and Freeze do work interestingly together, if you're using haze bombs. I've done that with another bomber, he used Shivermist (freeze) and I use Voltaic Tempest (shock) in FSC. The mass zombies just sat there, utterly confused. First, they're frozen! Then, they're shocked! Derp, but hey, freeze breaks, they can move! Only, they immediately freeze again! Then shock! It was better than either one alone, they didn't even swipe at people in front of them half the time. Fire plus Freeze doesn't work quite as well, because it takes time for the one status to impact the other.
I agree with Culture, as best as I can tell, poison doesn't increase the amount of damage they take from fire or shock ticks. But that doesn't mean it isn't stacking, the poison will impact them in other ways.
Poison does affect enemies and status. I do 2-3 more damage per tick when i mix a venom veiler. Small but i can see it.
As far as I know they don't, if you set someone on fire and stun them, I think that the fire goes away.