The new Call of Duty Zombies map, The Tomb, introduces a returning Wonder Weapon: the Staff of Ice, originally from Black Ops II's Origins. This guide details how to obtain it.
Can You Get the Staff of Ice from the Mystery Box on The Tomb?
While the Staff of Ice, like its Black Ops II counterpart, requires three parts, you can get lucky and find it in The Tomb's Mystery Box. However, this relies entirely on chance, even with the "Wunderbar!" GobbleGum. The Ray Gun is also a possibility, making this method unreliable. Building the Staff offers a guaranteed acquisition.
How To Build the Staff of Ice on The Tomb in Black Ops 6 Zombies
Obtaining the Staff of Ice Monocle

The first part, the Monocle, drops from the first Shock Mimic you eliminate in a match. Simply interact with it to add it to your inventory.
Obtaining the Staff of Ice Head Piece

The Head Piece and Staff parts require similar puzzle solutions and a survival lockdown. These can be obtained in any order.
To get the Head Piece, locate the cave painting in the Neolithic Catacombs. If the wall isn't illuminated, activate a Dark Aether lantern nearby; the fire will shift between lanterns until one illuminates the painting, revealing Roman numerals. Shoot these numerals in ascending order (I to X). A correct sequence triggers a lockdown. Survive the ensuing zombie onslaught to claim the Head Piece.
Obtaining the Staff of Ice Staff Piece

The Staff piece is acquired similarly. In the Tombs room, manipulate the Dark Aether lanterns to illuminate the Bull Mural (head facing left). Shoot the Roman numerals in ascending order (I to VIII). Survive the subsequent lockdown to obtain the Staff piece.
Completing the Staff of Ice
With all three parts, go to the Dark Aether Nexus (after opening the Door to Nowhere, if necessary). Place the parts on the central structure. Defend the Staff during assembly from a wave of enemies. Success yields the completed Staff of Ice.
Call of Duty: Black Ops 6 is available now on PlayStation, Xbox, and PC.