Burrowing ShotSource Weapon Master's Handbook pg. 21
You lodge your ranged weapons within your target’s body.
Prerequisites: Dex 13, Deadly Aim, base attack bonus +9, weapon training class feature with a ranged weapon.
Benefit: When you successfully hit a creature with a ranged attack, as a swift action, you can have the weapon (or its ammunition, for projectile weapons) lodge itself within the creature’s body, causing the creature to take a –2 penalty on ability checks, attack rolls, saving throws, and skill checks as a result of the intense pain. Penalties from multiple lodged weapons do not stack. If the creature is a spellcaster, it gains a 25% spell failure chance with all spells it casts that include somatic components. This penalty can be removed with the treat deadly wounds use of the Heal skill or by removing the lodged weapon as a standard action, which ends the penalties and causes the creature to take an amount of damage equal to the weapon’s base damage (without any bonuses).