Hell's Retriever

The Hell's Retriever is a Wonder Weapon and a tactical item introduced in the zombie map, Mob of the Dead for Call of Duty: Black Ops II. The Hell's Retriever can be obtained by feeding six zombies to each of the three Hellhound heads.

The locations of the the three Hellhound heads are as follows: Once the three Hellhound heads have receded into the wall, and the drawn Hellhound head is glowing, an area will open up beneath the sign of the three dog  heads down in the Citadel Tunnels. In this room will be the Hell's Retriever, awaiting to be picked up.
 * In the 'Broadway' cell block, located near the B23R.
 * In the infirmary adjacent to the Afterlife power box.
 * Near the workbench on the lower level of the docks.

When thrown, it can pierce through multiple zombies at once eventually returning to the player. It can also be charged, which adds more damage and distance. This can be done by holding down the tactical button for a maximum of two pulses. If the player throws it towards a Power-Up, it will retrieve the power-up and bring it back to the player.

Players will not lose the Hell's Retriever, even if they bleed out. Throwing it does not get rid of it, as it simply returns to the player. However, it takes a while for it to return to them. Additionally, the player has to wait for the 4-second cooldown before it can be thrown again. The Hell's Retriever has the ability to kill zombies instantly (if charged twice) until round 20. It is also very effective when fighting Brutus.

Hell's Redeemer
The Hell's Retriever can be upgraded into the Hell's Redeemer by completing a series of tasks. As long as it is charged, it is an insta-kill weapon. In addition, it can be charged three times as opposed to only twice with the Hell's Retriever. The Hell's Redeemer is only obtainable in Original Mode.

Steps to obtain the Hell's Redeemer

 * 1) Obtain the regular Hell's Retriever.
 * 2) Fly to the Golden Gate Bridge.
 * 3) Kill at least 30 zombies on the bridge using only the Hell's Retriever and wait for the round to finish. Shooting a weapon or using melee attacks may stop the streak. Once this step has been successfully completed, the player will hear the noise of entering Afterlife mode at the end of the round.
 * 4) Return to the prison via an Electric Chair.
 * 5) Throw the Hell's Retriever into the lava pit underneath the drawing of Cerberus near the B23R. If done correctly, the Hell's Retriever will not be returned to the player and the Afterlife noise will be heard.
 * 6) Wait for the round to be completed.
 * 7) Travel to the Citadel Tunnels where the Hell's Retriever is obtained. If previous steps have been done correctly, the Hell's Retriever should be absent and the aura should be blue rather than red. The Hell's Redeemer can now be picked up in Afterlife.

In multiplayer, every player can obtain the Hell's Redeemer, but each player has to do the steps themselves. However, multiple players can do the steps simultaneously.

Achievement/Trophy
Feed the Beast (10 / Bronze Trophy ) - In Mob of the Dead, obtain Hell's Retriever.

Trivia

 * The three Hellhound heads may be a reference to, Hades' triple-headed dog and guardian of the underworld.
 * The Hell's Redeemer is the first upgradable tactical item to appear in Zombies.
 * The Hell's Retriever has a fiery appearance whereas the Hell's Redeemer has an ethereal appearance, though it still appears to be composed of molten rock.
 * The Hell's Retriever is the first tactical item that can be acquired without the need of the Mystery Box.