Hydaelyn

You target a creature you can see within range, putting its physical form through the devastation of rapid aging. The target must make a Constitution saving throw, taking 10d12 necrotic damage on a failed save, or half as much damage on a successful one. If the save fails, the target ages to the point where it has only 30 days left before it dies of old age, suffering disadvantage on attack rolls, ability checks, and saving throws, with its walking speed halved. Only the Wish spell or Greater Restoration cast with a 9th-level spell slot can end these effects and restore the target to its previous age.