Caustic Critical (Combat, Critical)

Prerequisite: Critical Focus, BAB +9.

Benefit: When you score a critical hit with an attack that deals acid damage, you also deal acid damage to every foe adjacent to your target. The acid damage dealt is equal to 1d6 per critical multiple for critical hits made with a weapon, and equal to 1d6 for every 2 levels of a spell (minimum 1d6) for critical hits scored with a spell.

Special: You can apply the effects of only one critical feat to a given critical hit unless you possess Critical Mastery.