Maddening Whispers 2014

You whisper a string of Void Speech toward a target within range that can hear you. The target must succeed on a Charisma saving throw or be incapacitated. While incapacitated by this spell, the target’s speed is 0, and it can’t benefit from increases to its speed. To maintain the effect for the duration, you must use your action on subsequent turns to continue whispering; otherwise, the spell ends. The spell also ends if the target takes damage.