Genjutsu: The Sound of Drums is another of Kisui's Rinnegan techniques. By activating the genjutsu via eye contact, the victim's mind begins repeating a simple pattern. Four drum beats in a second by second loop, constantly repeating in their mind. The sound of it tears away at the victim's mind, leaving them mentally weak until their mental state deteriorates completely, leaving them completely insane. The way this works is it plays havoc on the brain's capabilities of identifying touch, smell, sounds, sights, etc. The brain detects this sound as an anomaly, so it shuts down the auditory senses, rendering them basically deaf. That doesn't work and the sound still plays, so it starts shutting down the senses, one at a time until there's nothing left to shut down. The sound's still playing