Poison Mage

Reading some stuff here on Cassio, I thought id list a few ways ive seen poison done in different games. Not proposing any particular one of these as a solution, just putting them out there for the Cassi community.

-Poison must stack up to a certain level, is initially harmless and decays, but once enough poison builds up a nasty DoT will trigger. (Dark souls)

-Poison stacks, doing no damage but halting regeneration while stacks persist (200 poison negates the next 200 regeneration etc). No idea how this could be brought into the game as anything but massively antifun though. (Desktop Dungeons)

-True damage over time. That's clearly stupid, so I'll expand the concept into a league system: Poison is a DoT that can stack multiple times. The stacks do not extend the duration, but rather reduce the amount that Mres reduces the damage (becoming true damage with enough stacks). This would lead to different play patterns based on how much Mres your opponent has: if they dont have much, poke to try to safely keep the basic DoT going, if they have a lot of Mres, commit to a fight to get the stacks up. To solve a logistical problem, you could use three types of poison from the skills, q applies green poison, w apllies purple, etc, each with their own debuff timer. Having any of the 3 (4? 5?) applies the DoT and additional types negate mres.

-Poison increases all other damage taken, stacking. If this was brought into league I'd like to see it last for a long time, maybe enough to cause lane swaps on both sides. The poison stacks slowly decay incrementally once they stop being applied. Would be interesting on a poke support, does little damage but sets enemies up to lose trades.

Leave your thoughts and any more non-standard poison concepts you might know, just in case this leads to some new thoughts in these Cassio threads.