Specify a creature you can see within the cast range, and try to destroy its sanity and personality. The target suffers 4d6 points of mental damage and must make an intelligence save.
Feeblemind 5e
Level: 8th
Classes: Bard, Wizard, Warlock, Druid
Casting Time: 1 Action
Range: 150 feet
Components: V, S, M
Duration: Instantaneous
When the saving throw fails, the creature’s Intelligence and Charisma become 1. The subject creature will not be able to cast spells, activate magic items, or even understand language or communicate intelligently. But the creature can still identify, follow, and even protect them.
The creature subject to the spell can make a new saving throw at the end of the day every 30 days. If the saving throw is successful, the spell effect ends.
In addition, greater restoration, heal, or wish can directly terminate the effects of the spell.