Fire Shield is a Daily power available to Wizards at 6th level[AP:106]
Fire Shield
Wizard Utility 6
You are swathed in rippling flames that turn away both fire and chill but scorch anyone who strikes you.
Daily ✦ arcane, fire
Personal
Effect: You gain resist 10 cold and resist 10 fire until the end of the encounter. Whenever a creature makes a melee attack roll against you, it takes 2d6 + your Intelligence modifier fire damage. No creature can take this damage more than once per turn.