Alright so what you want to do is roughly:
1. Pick a mob, like a boss, that won't die right away and won't kill you.
2. Open up Object Explorer, refresh it all, and select their Monster entry.
3. Save the right side panel using the Save button. This dump goes into your Logs folder.
4. Cast your caustic arrow, and if you're sure they are under the effects, Refresh the right side panel and save it again.
Now, you can use something like
Code Compare or any other comparison tool really, and check for differences in a few areas:
1. Stats, as if they have a harmful stat on them from the caustic arrow, then it should stand out.
2. Auras, if they are standing in the cloud, they should have a very specific aura you can check for.
3. Actual Health values, under the LifeComponent, you should find a regen value, although I think this would be a bad way to track it because if their regen surpassed your degen, or other things were DoTed on them, it'd not be accurate.
Give that a try and see if you can find something specific to identify what you're after. I'd say start with Auras first, then Stats, then actual fields in components. Play with that and let me know if you can or can't work it out and I'll take a look at it when I next get a chance if not. Good luck!
