pf2e.fyi
From Pathfinder Lost Omens The Mwangi Expanse, which isn't enabled.

Piercing Quills

FEAT 9
Prerequisites Spine Stabber

Your quills can dig particularly deep into the flesh of your opponents. Your quills unarmed attack deals 1d4 bleed on a critical hit.

Pathfinder Lost Omens The Mwangi ExpanseOGL