From Pathfinder Secrets of Magic, which isn't enabled.

Urgent Upwelling

FEAT 6

Activity reaction

Prerequisites Wellspring Mage Dedication

Frequency once per 10 minutes

Trigger An enemy reduces you to 0 HP, an enemy critically hits you, or you critically fail a saving throw against an enemy's effect.

Defeat lets you to tap into your wellspring. Attempt the flat check for wellspring magic. If you critically succeed, you can choose to forgo gaining a temporary spell slot to instead have the triggering enemy undergo a wellspring surge. This surge functions just as it would for you, the only difference being that it emits from the enemy.

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