- "Unless its snappin' at us, who gives a fuck about what the wolf's doin'?"
- — Finn O'Leary
Cerberus is a dog head seen in the Zombies maps Mob of the Dead and Cell Block in Call of Duty: Black Ops II. Cerebrus returns in Call of Duty: Black Ops 4 in Blood of the Dead. It also makes an appearance in Green Run as a boss in Call of Duty: Mobile. It is also a boss in the Battle Royale mode.
There are three dog-head markings on the wall across the map: in the Infirmary, in the Docks and on the Broadway, under Electric Cherry.
A head resembling a Hellhound will spawn on the wall when a zombie is killed near one. Cerberus will eat zombies killed near it (although if it is already eating one, it will not take a zombie killed during the eating process), and after it has eaten six zombies, it will vanish into the wall. After feeding each of the heads six zombies, a wall in the Citadel Tunnels will open, revealing the Hell's Retriever. One of the three heads is also featured in Cell Block, in the starting room (where the B23R is bought). Since the Hell's Retriever is not available in Cell Block, feeding Cerberus' head enough zombies will make a random power-up spawn and rise out of the lava pit below.
- The player will take very slight damage when touching one of the heads.
- Cerberus pauses for a moment after devouring a zombie.
- Cerberus will not eat zombies that are killed while it is already eating one.
- Zombies killed with the Zombie Shield or Nuke cannot be fed to Cerberus. In addition, it will not eat crawlers (zombies with dismembered legs) or Brutus.
- There are three heads, each one must be fed six zombies, which is likely a reference to the number "666".
- Above the entrance to the Hell's Retriever room is a piece of sheet metal with three dog-head markings. These markings can also be seen on the walls where a head will spawn from. For every head fed, one of the three head markings will light up. Once all three are lit, the wall will disappear, allowing access to Hell's Retriever.
- In Greek mythology, the three heads of Cerberus represented: Past, Present, and Future. The head at the docks represents the past (where the prisoners came in), the head in between the cells represents the present (the prisoners in jail) and the head near the roof represents the future (the escape plan.)