http://www.newsweek.com/call-duty-black-ops-4-zombies-ix-easter-egg-guide-full-walkthrough-1173546

Call of Duty: Black Ops 4 Zombies has proven to be a challenge for the community to unpack, but the Easter egg for IX has finally been solved by SmartGuy316, MrRoflWaffles and Liam Palmer. With their help, we’ll walk you through the process of getting it done.

This guide assumes you have the following things: