I am not sure on the level of a spell like this.
School: Transmutation
Level: Cleric X+1, Druid X, Wiz/Sorc X
Casting time: 1 minute
Duration: 1hr/level
Range: Touch
Target: Creature touched
You draw the power of an elemental plane or an elemental spirit into the target. When casting this spell, you must choose an energy type to infuse the target with. For the duration of the spell they gain resistance ZZ to that energy type. In addition all natural and weapon attacks (ranged or melee, but not spells, SP, or SU abilities) deal an extra (die size) of damage. In addition their body radiates this energy. Any time a creature attempts a melee attack against them, it is dealt (die size) in damage.