Pincushion (Pathfinder Feat)
From D&D Wiki
If the first arrow doesn't kill them, the tenth might. Each consecutive hit with a bow or crossbow attack does progressively more damage to the target.
Prerequisite: Martial Weapon Proficiency, Bow or Crossbow, Dex 16, BAB 9
Benefit: When you hit a target with a ranged weapon, you gain +1 bonus to damage on further hits on the same target. This bonus is not cumulative. This bonus lasts for 10 rounds.