Another witcher inspired potion! I like the potion that damages undead that just hang out near you. Wonder if Pathfinder needs that?
Corpsebane Item 1+
Alchemical Elixir Consumable
Usage held in 1 hand; Bulk L
Activate

This flask filled with the essence of undead distilled and purified with prayer. When consumed, you emit a faint light out to 30 feet. Any undead in the area must make a Fortitude saving throw or they are damaged by holy energy at the start of their turn or when they enter the area. They must repeat this at the start of any turn in the area or when they enter the area.
Corpsebane (Lesser)Item 1
Price 3 gp
Bulk L
Saving Throw DC 17 Fortitude. It deals 1d3 positive damage.
Corpsebane (Moderate)Item 3
Price 10 gp
Bulk L
Saving Throw DC 19 Fortitude. It deals 1d6 positive damage.
Corpsebane (Greater)Item 11
Price 250 gp
Bulk L
Saving Throw DC 28 Fortitude. It deals 3d3 positive damage.
Corpsebane (Major)Item 17
Price 2,500 gp
Bulk L
You Saving Throw DC 37 Fortitude. It deals 2d6 positive damage.