This solid, heavy, hovering, "companion" crystal ball is a remote spellcasting focus. It can be used by the attuned from up to 120 feet away but requires manual activation. By default, it follows the attuned wherever they go automatically, hovering just over their shoulder. It can be commanded to move in any number of ways. It sits inert when unattuned, de-activated, or commanded to hold still. Other Eye can be telepathically commanded to move 60 feet in any direction as a bonus action on the user's turn so long as a line of sight is maintained or Other Eye is being used to see. Otherwise, movement of Other Eye is made with some room for error determined by the DM. It may be that movement and sight through the Other Eye can be performed and maintained without the attuned having to enter a trance-like state or close one's eyes, everyday waking actions continuing seamlessly.

While scrying with this crystal ball or using its Find Familiar function, one has truesight with a radius of 120 feet centered on the spell’s sensor.

This crystal ball can cast Feather Fall on itself at will an unlimited number of times so long as it has been attuned to and activated.

The orb regains either 5 or 2d4 charges after a long rest, once per day. Casts:
Kinetic Jaunt for 1 charge (Must target Other Eye itself)
Light for 1 charge (Must target Other Eye itself)
Spiritual Weapon for 2 charges (Instead of a weapon being summoned, Other Eye itself is embued with arcane energy and performs as the weapon itself, dealing bludgeoning damage instead of force damage should one choose. Either way, on a hit, roll 2d20: if the total is less than 7, Other Eye shatters irreparably)
Catapult for 2 charges (Other Eye itself must be the object used as the "ammunition" for this spell. On a hit, roll 2d20: if the total is less than 7, Other Eye shatters irreparably)
Immovable Object for 2 charges (Must target Other Eye itself)
Modify Memory for 4 charges

13 inches in diameter, it offers about 4 square feet of storage due to the shape and thickness, but realistically fits about 200 Liters of any liquid. When disassembled a certain way, the average human head could fit snugly within.

ATTUNEMENT NOTE: a sacrificial eye is used in the attunement ritual, and it must have belonged to the attuner. If one has already sacrificed an eye to create an Other Eye or attune to another model in the past, there is no need for the attuner to sacrifice another when re-attuning or attuning to similar models later.

Notes: Sense: Truesight, cleric (knowledge or arcana), sorceror (clockwork soul), warlock (the genie or the celestial), artificer (any), or wizard (any), Summoning, Control, Scrying, Detection, Utility, Combat, Container, Focus, Artificer, divination