Feat: Explosive Metamorphosis

You use additional primal energy to transform, creating a burst of elemental energy to complement your transformation. If your next action is to cast a non-cantrip morph or polymorph spell, select acid, cold, electricity, or fire. Your transformation creates a 5-foot emanation around your new form that deals 1d6 damage of that type per rank of the spell. Each creature in that area attempts a basic Reflex save against your spell DC.

If your polymorph action had a trait corresponding to an energy type, you must select that one if possible. This action gains the trait corresponding to the energy type selected.