From Pathfinder Lost Omens Character Guide, which isn't enabled.

Tomb-Watcher's Glare

FEAT 5

Prerequisites death warden dwarf heritage

When you critically hit an undead creature, or an undead creature critically fails a saving throw against one of your abilities, you drive your divine wrath home in your enemy's heart. The undead is Enfeebled 1 for 1 round.

Pathfinder Lost Omens Character GuideOGL