pf2e.fyi
From Pathfinder Lost Omens Impossible Lands, which isn't enabled.

Glowing Horn

ANCESTRY FEATURE

Your horn reacts to psychic energy by softly glowing. The horn emanates dim light in a 10-foot emanation until the start of your next turn whenever you use an occult action you gained from an ancestry feat, cast an innate occult spell, or Cast a Spell that has the mental trait.

Pathfinder Lost Omens Impossible LandsOGL