Consider Your Options (No Belief). This ablility offers 3 options: Melee Trickery, Medical Wizardry and Mana Conjury, increasing damage, healing and giving mana respectively.
Upon using it the player will either lose 5 INT or gain 1 INT, making it most effective as a last resort. Using it regularly will result in very low INT levels. Having very low INT makes you unable to use the power. There are no time or frequency restrictions and no cost besides potential loss of INT.
The wizard, rogue and thief possess this ability.