Eye of Iron Sight

Wondrous item, legendary (requires attunement by a creature missing an eye)

This metal sphere is the size of an eyeball with a glass iris. Its weight is negligible. Even if you aren't attuned to the sphere, it functions like a normal eye while it's in your eye socket; it doubles as a magic spyglass if you look through only the sphere.

If you're attuned to the sphere and have it in your socket, attacking at long range doesn't impose disadvantage on your ranged weapon attack rolls, and creatures gain no benefit from half cover against your ranged attacks. You also gain the following two benefits:

Headshot. Whenever you score a critical hit on a ranged weapon attack, the target must also succeed on a DC 17 Constitution saving throw or be stunned until the start of your next turn.

Iron Focus. Whenever you make a ranged weapon attack as part of the Attack action on your turn and haven't moved during this turn, you can choose to reduce your speed to 0 until the start of your next turn and enhance the accuracy of the attack. Each time you use this property, the number you need to roll on the d20 to score a critical hit on a ranged attack roll against that target is reduced by 1, down to a minimum of 15. This benefit ends once you score a critical hit, attack a different target, or move.

You may run or hide or fight,
better folk than you have tried.
Doomed are all who draw the sight
of the one with the iron eye.

Darkest depths to highest heights,
nowhere's safe for you to fly,
Cursed to never take last rites
by the ire of the iron eye.

From the shadows, brief sunburst,
iris glass reflects the sky.
See it now, it saw you first
did the gaze from the iron eye.