You can close the distance when a foe tries to move away.
Prerequisite: Base attack bonus +1.
Benefit: Whenever an adjacent foe attempts to take a 5-foot step away from you, you may also make a 5-foot step as an immediate action so long as you end up adjacent to the foe that triggered this ability. If you take this step, you cannot take a 5-foot step during your next turn. If you take an action to move during your next turn, subtract 5 feet from your total movement.
Pathfinder RPG Core Rulebook. Copyright 2009, Paizo Publishing, LLC; Author: Jason Bulmahn, based on material by Jonathan Tweet, Monte Cook, and Skip Williams.