Chink in the Armor (Combat)

You follow up a successful attack in the same spot.

Prerequisite: Knowledge (special, see below) 5 ranks or favored enemy (special, see below); Critical Focus, base attack bonus +9

Benefit: If you have the required ranks in the skill that would identify the target creature or the correct favored enemy designation and you deal a successful critical hit, your first attack against the same opponent the following round automatically threatens a critical hit if the attempt hits.

Special: If the automatic threat results in another critical, you do not gain the benefit of this feat on the following round.