You cause creatures to take extra damage when you affect them with a spell that has the acid or fire descriptor.
Benefit: The acid or fire effects of the affected spell adhere to the creature, causing more damage the next round. When a creature takes acid or fire damage from the affected spell, that creature takes damage equal to 2x the spell’s actual level at the start of its next turn. The damage is acid or fire, as determined by the spell’s descriptor. If a burning spell has both the fire and acid descriptor, the caster chooses what kind of damage is dealt by the burning spell effect.
Level Increase: +2 (a burning spell uses up a slot two levels higher than the spell’s actual level.)