Greenwatcher Feat 10
Source Pathfinder Lost Omens: Impossible Lands
Prerequisites Defy Fey
Your experience fighting against and alongside fey creatures is nearly unrivaled. Any weapon you wield or unarmed attack you make against a fey creature is treated as cold iron. Whenever you critically fail a save against a spell cast by a fey creature, it's instead treated as a normal failure. Whenever you critically succeed on a Strike against a fey creature, the target is immediately subject to the effects of a Faerie Fire spell. For the purposes of counteracting this effect, it's an innate 2nd-level primal spell.
Traits
This rarity indicates that a rules element is very difficult to find in the game world. A rare feat, spell, item or the like is available to players only if the GM decides to include it in the game, typically through discovery during play. Creatures with this trait are rare. They typically can't be summoned. The DC of Recall Knowledge checks related to these creatures is increased by 5.
GunslingerThis indicates abilities from the gunslinger class.
InvestigatorThis indicates abilities from the investigator class.
RangerThis indicates abilities from the ranger class.