This amulet includes a small glass bead in the center. The coloration of the bead leads the viewer to think of an open eye staring outward. The way the colors shift in the light it even makes on believe that it could be moving, ever so slightly.
Once per duration the wearer can concentrate on a single target in view and invoke the activation word or phrase of the amulet. Once activated, the target must succeed on a mental saving through (concentration, wisdom, or similar). On a failed save, the amulet becomes the focus of distraction. Any time the amulet is in the target's field of view they will have disadvantage on all saving throws related to concentration, perception checks based on vision, or other mental focus. The target keeps seeing distracting motion in their peripheral vision, but when they look directly at the amulet, it just looks like a normal piece of basic jewlery.