Castigate

You lash out verbally at a group, the power injuring them and making their attacks less effective.  Up to three creatures of your choice that you can see within range take 5d8 psychic damage and must make Intelligence saving throws. Whenever a target that fails this saving throw makes an attack roll or a saving throw before the start of your next turn, the target must roll a d8 and subtract the number rolled from the attack roll or saving throw.  A successful save halves the psychic damage.