One of the most significant changes in Zombies for Call of Duty: Black Ops Cold War is the new tiers of damage each weapon has. The level your gun is at determines how much damage you are putting out. For example, a legendary tier weapon puts out much more damage than anything at uncommon or rare tiers. This makes your damage tier essential to manage and upgrade, making the giant hand Easter egg in Die Maschine a cool way to do so, although quite tricky to pull off. Get it done, though, and whatever weapon you are holding will instantly be upgraded to a legendary tier for free. Here is how to do the giant hand Easter egg.
Before we go into this, we highly recommend not attempting to do this Easter egg in a solo match. While only one person is needed to do this, it is much easier to have a person or two guarding your back, so you can focus on what is in front of you. You will be facing the hallway in Medical Bay that you cannot enter and really will need to focus on there, leaving your backside open for attack.
Before you can do the Easter egg, get whatever weapon you want to be upgraded and pack-a-punch it. This can be any gun except the D.I.E. Shockwave since that cannot have its damage upgraded. We recommend something with decent accuracy as you will be shooting buttons down a hallway. A shotgun can work, but an assault rifle will get the job done much easier.
After getting your packed weapon, use an anomaly to go into the Dark Aether. There are four buttons you need to shoot down the hallway. You will know you did it when a green light turns on above the door you shot each at. The locations are in the screenshots below.
Now that all four lights are on, you will see the window on the left door light up green. You need to shoot the red button by the door to make a giant zombified hand come out of the door and swipe. Your goal is to time your shot perfectly and get 15 kills on zombies as they run past this door. If you get kicked out of the Dark Aether, advance to the next round and jump back in.
Upon your 15th kill, a purple orb will rush to you, changing whatever weapon you are using to legendary, and the lights will turn off in the hallway. While getting a legendary weapon is nice, we would not necessarily recommend this as a great way to upgrade your weapon for a high round run. If you last long enough, you get enough salvage to do the upgrade yourself anyway, and you can always hit the box or activate something like the Coffin Dance Easter egg to get a legendary weapon. Regardless, that is how you can do the giant hand Easter egg in Die Maschine.