Primal Critical (Combat, Critical)

Prerequisite: Critical Focus, BAB +9

Benefit: Select one of the following damage types: acid, cold, electricity, fire, sonic. When you score a critical hit with an attack that deals damage of the selected type, your foe gains vulnerability 5 to that energy type. This vulnerability remains until all the damage you dealt with the critical hit is healed.

Special: You can apply the effects of only one critical feat to a given critical hit unless you possess Critical Mastery. You can select this feat more than once. Its effects do not stack. Each time you select this feat, you must choose a different damage type.