Mega Bomb
You can add a highly explosive additive to an alchemical bomb to turn it into a mega bomb. Throwing this bomb takes a 2-action activity instead of a Strike. This isn't a Strike, and you don't make an attack roll. The mega bomb explodes in a 30-foot burst within 60 feet. It deals damage as if each creature were the primary target, with a reflex save. On a failed save, a creature also takes any extra effects that affect a primary target (such as Off-Guard from bottled lightning). Though all targets in the area take splash damage as primary targets, there is no further splash beyond that area.
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.
You must physically manipulate an item or make gestures to use an action with this trait. Creatures without a suitable appendage can't perform actions with this trait. Manipulate actions often trigger reactions.