I need a poison Immune / resistant ability

I have been looking, but I can't seem to find a poison immune / resistant type of buff or ability. If anyone know of one, or a good way to come up with one please let me know. Thanks.

Maybe make a buff detection and if its a poisen ability like slow poisen, clear the specific poisen buff.

Okay, only problem with that is that it would have to check hundreds on units, is there no ability that can do this? If not, then maybe someone knows a very efficient way of just checking a certain unit type during a certain period for a buff or something.

If the person is attack and unit-type equals whatever, wait a second so the attack would be done and the effect would take place and then do If / Then / Else, if he has XBuff, then remove it.

I could have SWORN I posted about this... Sigh too late now. I will look in my history and see what I dig up...