Vex Cranium

Vex Craniums are severed heads of Vex that are used for many different purposes across Destiny 2's lifespan.

Overview
As a Relic weapon, wielding a Vex Cranium moves the user's camera to third person. All their active abilities become unable. Using the "fire" button makes the Cranium shoot a powerful elemental beam, its element depending on the activity it appears in. Once a cranium's energy is exhausted, it disappears from the user's hands.

Leviathan, Eater of Worlds
Vex Craniums first appeared in the Leviathan, Eater of Worlds Raid Lair where they were used against Argos, Planetary Core and it's rubble shell. In this encounter Guardians had to find Vex Craniums in the arena and bring them to an altar where they were charged with either Void, Arc, or Solar energy to be used to destroy Argos' matching elemental quantum mines it arms on its rubble shell to wipe out the Guardians.

In the second encounter against Argos itself the Craniums were used to use Argos' own attack against it by charging them with an elemental flame at an altar like before and guiding elemental orbs Argos used to charge its attack into one of its shields weak points to expose Argos.

Menagerie
The Vex Craniums made another appearance in the Season of Opulence's Menagerie. In this mission they were used in the Crystals encounter where the players needed to destroy Harpies to get Vex Craniums to destroy royal nectar crystals.

Vex Offensive
Vex Craniums appeared in Season of the Undying's flagship team-based mission known as Vex Offensive, where they were dropped by Gate Technicians and used to destroy Oracles that attempted to expunge the invading Guardians. They also played a role in the final encounter where they were used to weaken and destroy Crotheon, Gate Keeper or The Undying Mind's invulnerability shield so they could be damaged.

Dares of Eternity
Vex Craniums reappear in Dares of Eternity, where they are obtained by killing Xur's Headbearer Goblins, and used to take down the shields of the Gatekeepers of Eternity. They only appear in their Void variation, and are thus called Void Craniums.

Trivia

 * Vex Craniums are one of the few ways to cause friendly fire in Destiny.

List of appearances

 * Destiny 2
 * Curse of Osiris
 * Season of the Undying
 * Season of Opulence
 * 30th Anniversary Pack
 * Lightfall