Each Monster can be individually muted by selecting it and using the “Mute” button. All Monsters on an Island can be muted by using the “Mute All” button on the Castle on most Islands, the Nexus Nucleus on Magical Nexus or the Dish-Harmonizer on Ethereal Islets. Using the Mute and Unmute All buttons does not affect the individual volume settings you may have customized for each Monster.