Songfacts®:

• In September 2018, Avenged Sevenfold released a four-track EP linked to the release of the Call of Duty Black Ops 4 video game. Having been featured in all three of the Black Ops releases previously, it was a no-brainer for the game-developing company Treyarch to get them involved in a new installment.
  
  The EP contains a completely new song, "Mad Hatter," written for Black Ops 4, plus the other three tracks the band has written and recorded for the Call Of Duty: Black Ops franchise: "Not Ready to Die," "Carry On" and "Jade Helm."
• The game finds the central characters having to deal with a massive zombie uprising, but Avenged Sevenfold wanted to go in a slightly different direction with "Mad Hatter." M. Shadows told Kerrang: "The song is dark and brooding. We wanted to capture a difference feeling than a straight-ahead 'zombie killer' track. These songs are good places for us to experiment with our sound. I would put this in the category of 'dark alternative.'"
• Asked whether "Mad Hatter" was written with Call Of Duty in mind or if it was a leftover cut from The Stage sessions, M. Shadows said:
  
  "I did a Twitter takeover where a fan asked me about doing music for Black Ops 3. The team at Treyarch saw it and asked us to participate. I went into the studio and saw what they were working on. We only had a month to get them a finished product, because of our European tour. We wrote what we felt would be a departure for not only us, but Treyarch as well."