Immunity

[Hale_32bit]

Ring, it would seem simpler to change immunity to allow targetting but no damage or conditions (since removing conditions isn't a condition on the target). 

What about psyсhic immunity, mind control and other psyсhic enchantments?

[Halewijn]

So, what is the conclusion of this tread? can you target creatures with the poison immunity tread with plagued?  I suppose not because this would be in contrast to the psychic immunity with charm/mind control. It would make sense with some of the creatures though.

[Zuberi]

You can not target poison immune objects with a spell that has the poison subtype, which I believe includes Plagued. This is covered in the codex if you look up Immunity. The one exception to this is targeting Hydro Immune objects with a spell that has extinguish, as covered in the Rules Supplement.