Pernicious Poison Feat 2
Source Pathfinder Player Core 2
You can add a toxic additive to an alchemical poison to make it splash poison on its target. A poison with this additive deals an amount of poison damage equal to the poison's level if the target succeeds at its initial saving throw against it. A target that critically succeeds at its saving throw against this poison still takes no damage.
Traits
Anything that doesn't list another rarity trait (uncommon, rare, or unique) automatically has the common trait. This rarity indicates that an ability, item, or spell is available to all players who meet the prerequisites for it. A creature of this rarity is generally known and can be summoned with the appropriate summon spell.
AdditiveFeats with the additive trait allow you to add special substances to alchemical consumables you create when you use Quick Alchemy to create a consumable (you can't use additives with quick vials). You can add only one additive to a single alchemical item, you can add an additive only once per round, and most additive abilities specify a subset of alchemical consumables you can add them to.
AlchemistThis indicates abilities from the alchemist class.