From Pathfinder Guns & Gears, which isn't enabled.

Injection Spear

ITEM 0

UNCOMMON INJECTION REACH

Price 3 gp

Usage held in 2 hands

Bulk 1

Category martial

Group spear

Damage 1d8 piercing

A hollow receptacle inside this spear's head can store a single dose of poison. A sliding trigger along the spear's shaft can inject the loaded poison into a damaged target.

Pathfinder Guns & GearsORC