Burn it off

Ranged spell, at-will
Special: You take half-damage on the next castings of this spell in a battle.
Target: Nearby enemy
Attack: Charisma + Level vs. PD
Hit: 2d6 + Charisma fire damage.
Natural even hit: -2 from target`s AC until the end of battle
3rd level spell 4d6 damage
5th level spell 6d6 damage
7th level spell 9d6 damage
9th level spell 8d12 damage