Each of the missions in Call of Duty: Black Ops 4 zombies has a secret Easter egg song that players can unlock by completing a set of requirements. We’ve already shown you how to unlock a few of these, so this time we’re going to focus on how to unlock the Mad Hatter Easter egg song in Black Ops 4 zombies, on the map IX. Here’s what you need to know to unlock the IX secret song.

How to Unlock the Mad Hatter Song on IX

In order to unlock the Easter egg song on IX you’re going to need to do something similar to what you did to unlock the secret song in Voyage of Despair. Spread throughout the arena, players will be able to find several coins (four in total) that they will need to shoot with a weapon. Upon shooting all four of the coins, the secret song will unlock, allowing you to listen to it. We’ve broken down the locations of each coin below, so let’s dive in and get started.

Coin #1

The first coin on our list can be found inside of Odin Tower, near the entrance. The actual coin can be spotted through a metal gating when you look towards the entrance to where you spawn in to the Arena.

Coin #2

This second coin can be found inside of the Burial Chamber in Ra Tower. Look for one of the braziers in the corner—near a golden statue near a piece of wall that juts out of the wall (where the torch rests). The coin itself can be found between the two chests between the statue and the brazier.

Coin #3

To find the third coin players will need to make their way to the entrance of Danu Tower. Once here, look out of the window on the bottom floor. You should see a set of stairs to the right, as well as a boardwalk above. This coin can be found pinned against the wood of the boardwalk above you. This coin is actually located outside of the main play area, so be sure to look for it very carefully.

Coin #4

The final coin that you need to find and shoot will be found inside of Zeus’ Altar Room. Look for the statue on the back wall—near the weird zombie skeletons that jut out from the ground—and then check the base of the statue’s right side to spot the coin shining brightly, waiting to be shot.

With all four of the coins activated, the Mad Hatter Easter egg song should begin to play. Enjoy it and get back to kill all the zombies that come after you. Make sure you also learn how to Pack-A-Punch on IX and be sure to head back to our Black Ops 4 guides for even more help.