Additionally, Undead Nightmare adds more animals to the game's biosphere, new «dynamic
events,» eight new zombie characters for use in
multiplayer, and a new Undead Overrun
cooperative mode.
During the community reveal
event for Call of Duty: Black Ops 4, which focused on the
multiplayer modes both regarding the
cooperative and competitive features, Treyarch revealed that there will be two versions of the Zombies mode present in Black Ops 4, and the team is doing something completely new with one of the modes.