As a reaction, which you use when you are hit by an attack, jets of water shoot out from you. If the creature who damaged you is within 10 meters, it must make a Reflex saving throw.
On a failure, it takes 2d10 bludgeoning damage and is pushed or pulled 2 meters away from you or toward you if it is Medium or smaller.
On a critical failure, it takes twice as much damage and is pushed or pulled 4 meters away from you or toward you if it is Medium or smaller.
On a success, it takes half as much damage.
On a critical success, it takes no damage.
You can increase the damage by 2d10, push the creature an additional meter, and affect a creature of a larger size for each additional mana expended.