Sticky Bomb
You can mix in a sticky additive to an alchemical bomb to make its contents adhere and continue to deal damage. A creature hit by a sticky bomb also takes persistent damage equal to and of the same type as the bomb's splash damage. Use the splash damage amount listed in the bomb's stat block, even if you used an ability to change the splash damage dealt. If the bomb already deals persistent damage, combine the two amounts.
Traits
Feats 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.
This indicates abilities from the alchemist class.