Formian Biotoxin Feat 5

Your body generates a special biotoxin that you can deliver with your jaws. Your jaws unarmed attack deals an additional 1d4 persistent poison damage. Additionally, on a critical hit with your jaws Strike, the target must succeed at a Fortitude save against the higher of your class DC or spell DC or be enfeebled 1 for 1 round (or 1 minute on a critical failure).