You transform your eldritch blast into a lightning blast. A lightning blast deals electricity damage and gains a +2 bonus on its attack roll and a +2 bonus on caster level checks to penetrate spell resistance. These bonuses are doubled against a target who is wearing metal armor or whose body is composed primarily of metal. In addition, a target who is soaked or immersed in water or a similarly conductive liquid takes an extra 2d6 points of damage from a lightning blast.