From Pathfinder Rage of Elements, which isn't enabled.

Elemental Explosion

FEAT 6

Activity 2 actions

Requirements You're raging, and you haven't used this ability since you last Raged.

You unleash the energy roiling within you, exploding elemental matter in a 15-foot emanation. Each creature in the area takes 1d8 damage per level you possess, with the same type you chose for elemental rage. Each creature in the area must attempt a basic Reflex. Elemental Explosion gains the trait of your element.

Pathfinder Rage of ElementsOGL