Thundergun

The Thundergun is a weapon featured in the zombie mode of Call of Duty: Black Ops, and can be found via an easter egg in the campaign mission "Numbers". The Thundergun is a cannon-shaped weapon that fires directional blasts of incredibly strong wind. It has no iron sight. It appears to be able to kill large numbers of zombies with a single shot, sending them flying backwards or up. Those who are not killed by the wind blast are thrown backwards and will remain on the ground for a few seconds before getting back up. The Thundergun holds two rounds in a magazine, holds twelve reserve rounds and can only be reloaded when all shots have been fired. When Pack-a-Punched it becomes the "Zeus Cannon", it has an increased magazine size of 4 and carries 24 reserve rounds. It has increased range and radius, and can now knock over and slightly damage zombies off screen. The Thundergun is most important during the later rounds as it is useful for clearing large groups of zombies in order to reach a downed teammate or make an escape. It is extremely useful when swarmed because it will easily kill a large group of zombies in one shot.

It is often used as a reserve weapon, as it has a low amount of ammunition and a moderately slow reload. It can only be reloaded when the entire magazine is empty, except on PC, Wii, and in the single player campaign mission Numbers, where one can execute a partial reload. Because of this, it is advised to shoot any extra rounds in a magazine before obtaining a Max Ammo. Wasting ammo on one zombie is not advised. It is also a decent weapon against Hellhounds as it can easily take large numbers of them out and will always kill them in one hit. Since the last hellhound will always drop a max ammo, it is a good strategy to use the thundergun on the hellhounds until they are either all dead or the Thundergun is on its last drum, in which case the user should switch to their secondary if there are any hounds left.

Finding the Thundergun in the Campaign
The Thundergun appears in the singleplayer level "Numbers" as an easter egg, similar to the Ray Gun in "Little Resistance." The steps and video on how to do it are as follows:
 * 1) After the interrogation scene ends there are six big white canisters in front of the player on the walls. (Note: they are not the small propane tanks on the ground; they are the big white ones).
 * 2) Shoot, or throw grenades at all six canisters until Nova-6 comes out. (Note: you must cause damage to the canisters before your attackers do. You might want to flashbang your attackers too).
 * 3) Run past the ladder to a small room connected to where you first start the mission.
 * 4) If done correctly the player will see a black tape sticking out of a cassette player next to the door way.
 * 5) Hold down the action key and the tape will disappear from the cassette player, or the obvious shake in the screen as cue.
 * 6) Continue on until you get to the first of Clarke's weapon caches, behind the fridge after the rooftop jump.
 * 7) Look to the left and you should find a cassette player.
 * 8) When at the cassette player, press the use button and notice the cassette go in.
 * 9) If done correctly, notice the tape goes in and the player makes several tunes, and the screen shakes.
 * 10) The Thundergun will appear on the wall above the cassette player.

The gun found in "Numbers" comes with two shots in the magazine and 12 shots in reserve. It also gains a full ammunition refill after sliding down the pipe and at the second weapons cache. Because of this, it becomes very useful when playing on Veteran. In essence, it works much like an extremely powerful shotgun, throwing and almost always instantly killing anyone caught in its massive spread, often with enough force to tear off limbs.

You can swap out for another weapon, and you will be able to pick it up. But sometimes after picking up another weapon, the Thundergun becomes unusable because of a bug. Also if you jump up onto the table with the cassette player and look behind it you will see a arrow like some that you see in Nazi Zombies.

Zombies
The Thundergun can be obtained in the Mystery Box for 950 points in the maps Kino der Toten and Ascension, and the revamped version of Nacht der Untoten. It shoots a compressed air shock-wave blast that knocks any zombies backwards that survive the original hit. When Pack-A-Punched, it becomes the "Zeus Cannon". The Zeus Cannon carries 4 shots at a time rather than 2, and its reserve capacity is 24 instead of 12. Despite not being usable, the Thundergun makes an appearance in "Five" in the weapons-testing lab. This likely means that the Thundergun was found and is being reverse engineered. Various references throughout World At War Nazi Zombies are stating that the Americans were experimenting with Element 115, one notably being the Shi No Numa starting room secret radio message. This may be referencing the Winters Howl, which is confirmed to be powered by Element 115 and is most likely manufactured by the Americans, as it can be seen in development in the Pentagon science labs.

Video
 Video:Call Of Duty:Black Ops Zombies New Badass Gun(Thunder Gun)|The Thunder Gun in action. Video:Call of Duty Black Ops Kino Der Toten Every Weapon Upgraded! Missing ThunderGun(Chuck Norris Cannon)|The Thundergun pack-a-punched into Zeus Cannon Video:Upgraded Thunder Gun and Ray Gun on Kino der Toten|The Upgraded Thunder Gun and Ray Gun Video:How to get the Thundergun in Black Ops Easter Egg|How to get the Thundergun in the level "Numbers".

Trivia

 * The Thundergun is the only gun in Zombies that can't aim down or reload at mid-clip.
 * The gun has "Osterezheniye" written on its side, which is the misspelled Russian word for "Warning", which correctly spelled is "Предострежение" (Predostrezhenie).
 * The two red glowing lights on the front of the canister when loaded into the gun indicate how many shots are left in the magazine, when upgraded there are three lights visible as one of them is hidden by other parts of the gun.
 * If zombies that are knocked down by the Thundergun's blast are attacked by players, they will instantly be back up on their feet, instead of slowly rising up.
 * Richtofen states that this weapon was invented by Ludvig Maxis, but was deliberately hidden from him.
 * The Thundergun and the Ray Gun are the only Wonder Weapons that can be found in campaign. These are also the only two Wonder Weapons to have an official pick-up icon.
 * The Thundergun deals no friendly fire damage in "Numbers".
 * There is an unusable Thundergun in a metal locker in "Five". It is in the same room as the unusable Winter's Howl and Death Machine.
 * On all consoles, when the Thundergun is being used, the Russians start screaming like zombies.
 * If the player turns off rag doll effects, zombies will not fly backwards when shot, just fall as if they were taken out by conventional weapons.
 * Occasionally, zombies caught at close range in the blast will not be affected at all, as if the weapon missed them entirely.
 * "Stainless Steel" can be seen written on the Thundergun.
 * The Thundergun was originally going to be a usable weapon on Five, as there are quotes in the games files for each character, as can be seen here
 * It is impossible for two players to have the Thundergun simultaneously.