1/ Don't know about negative health regen.
2/ For enviroEffect it is not possible.
Here are the limitations for enviroEffects:
// Note: there are limitations, since we're not using a projectile and nobody is actually shooting
// 1. no power bonus based on shooting unit's stats (nobody is shooting)
// 2. no power range reduction (there is no projectile, range = 0)
// 3. no AOE damage from explosions (targets are damaged directly without affecting anyone/anything)
// 4. no terrain damage
// 5. no self-destruct
// 6. no vanilla target morale loss when hurt; vanilla morale loss for fatal wounds still applies though
//
// 7. no setting target on fire (...could be added if needed)
// 8. no fire extinguisher
Thank you for listing the enviroEffects: limitations.
You've saved me a lot of trial and error.
Corpse cannot have grenade type as this make holes in recovery logic, but on other hand we could allow corpses to explode same as grenades :D
We could consider specab a precedent of this feature.
If the problem is that the unit no longer exists after the 'between turn' damage then using the corpse as a way to pass the explosion data into the next turn sounds like a good solution.
You can create identical armor, one of them with desired effect, and then switch them via startingconditions.
I hadn't considered using those variables for units other than X-Com's own soldiers.
That really opens up some interesting options, thank you for pointing it out.
(https://openxcom.org/forum/index.php?action=dlattach;topic=10107.0;attach=54891)
Tinkering with this looks like its going to be a lot of fun. 8)
Then make the corpse be the timed grenade, allready primed.
Even if the corpse itself cannot be the grenade (currently) your post reminded me of a script I saw posted by Greenscarf in the [Documentation][y-script] OXCE Script examples thread. (https://openxcom.org/forum/index.php/topic,5245.msg138195.html#msg138195)
Perhaps Greenscarf's 'Automatic Priming' script could be used to load enemy units with a pre-primed grenade that explodes on their death?
Although related its a bit off topic so as not to derail this thread I'll post a new topic in the [Modding -> Help] about using this script as a makeshift way to achieve something like the specab: 1 effect while using either enviroEffects: or decaying health. (Spawning a unit with builtInWeaponSets: that has a grenade? (https://openxcom.org/forum/index.php/topic,10116.0.html))