Reverse Energy

Casting Time: 1 reaction(when taking magic damage)
Range: Self - Components: S - Duration: 1 round
You have resistance to the triggering damage type
until the start of your next turn. Your first melee
hit deals extra damage of the opposite type equal
to half the original damage to a maximum of 10.
Fire - Cold, Lightning - Acid, Poison - Thunder, Radiant - Necrotic, Force - Psychic
At higher levels the maximum damage increases
by 5 for each slot level above 2nd