While you have this charm, you attract flies. As an action, you activate this charm to summon a barbed devil, two bearded devils, or three spined devils. All devils appear at once in unoccupied spaces within 30 feet of you. Each devil obeys your commands and serves you eagerly for 9 days or until it dies, whereupon the devil disappears. Once all devils summoned by this charm disappear, the charm vanishes from you.