You only have so much salvage to juggle between upgrading your weapon or your armor. Getting your hands on uncommon salvage is easy, but the challenge starts when you have to collect high-tier salvage for those later upgrades, such as the Legendary weapon rarity upgrade. This is where the Free Aether Tool, commonly dubbed as the ‘document’ easter egg, comes in. This upgrade allows you to upgrade your equipped weapon’s rarity for free. You only get one upgrade per game. The easter egg is time-sensitive, and once started, it requires you to have a high-damaging long-range rifle. We prefer a sniper rifle due to its superior magnification and high damage profile. If the damage is not great enough, you won’t be able to complete this easter egg. The document only spawns once you’ve turned on the power. Follow the on-screen instructions on how to turn on the power, or you can check out our complete guide here. Assuming you’ve turned on the power, return to the spawn location (Apartment Rooftops) and check the southwestern corner of the rooftops. You will find a document on the floor. Interact with it, and the easter egg will start.

In this easter egg, you’ll need to shoot down five moving targets in five separate locations. These locations are fixed, but you can only do this easter egg once. If you fail, you can’t do it in this game. You will have to restart and try the easter egg again.

Target #1 The first target appears in the “O” of the Konigshaus sign. Target #2 The second target appears directly below the sign in a broken window. Target #3 The third target appears in the “O” of the Korber sign. Target #4 The fourth target appears in a lit window on the top floor of the Der Dozent building. Target #5 The final target appears behind the “Der Dozent” sign.

After hitting the fifth target successfully, you will hear a unique sound in the background, and the Aether Tool will pop out of the ground. Make sure you’re holding the gun you want to upgrade the rarity for when picking up the aether tool.

The second target appears directly below the sign in a broken window.

The third target appears in the “O” of the Korber sign.

The fourth target appears in a lit window on the top floor of the Der Dozent building.

The final target appears behind the “Der Dozent” sign.

Here is a complete overview of where the targets will appear in the correct order:

Free Aether Tool Easter Egg On Mauer Der Toten  Free Rarity Upgrade Easter Egg    Cold War Zombies - 93Free Aether Tool Easter Egg On Mauer Der Toten  Free Rarity Upgrade Easter Egg    Cold War Zombies - 36Free Aether Tool Easter Egg On Mauer Der Toten  Free Rarity Upgrade Easter Egg    Cold War Zombies - 43Free Aether Tool Easter Egg On Mauer Der Toten  Free Rarity Upgrade Easter Egg    Cold War Zombies - 82Free Aether Tool Easter Egg On Mauer Der Toten  Free Rarity Upgrade Easter Egg    Cold War Zombies - 20Free Aether Tool Easter Egg On Mauer Der Toten  Free Rarity Upgrade Easter Egg    Cold War Zombies - 39Free Aether Tool Easter Egg On Mauer Der Toten  Free Rarity Upgrade Easter Egg    Cold War Zombies - 33Free Aether Tool Easter Egg On Mauer Der Toten  Free Rarity Upgrade Easter Egg    Cold War Zombies - 78Free Aether Tool Easter Egg On Mauer Der Toten  Free Rarity Upgrade Easter Egg    Cold War Zombies - 85