Element 115 (Ununpentium) plays a role in the Zombies back-story. According to the radio messages in Shi No Numa and Der Riese and by character quotes, it is extensively used by Group 935. In the Zombies storyline, Element 115 is harvested from meteorites that have been found in Shi No Numa, Der Riese, Groom Lake (Area 51), Tunguska, and the moon. One of these meteors can be seen in Shi No Numa, and until the release of Call of Duty: 'Black Ops, this was the only meteor to be found in the maps. Meteor fragments can be found in Kino der Toten, Call of the Dead, and Shangri-La. Pressing the 'use' button on all three fragments in each map will activate that maps's musical easter egg. Said meteors are red in color, emit strange noises, and have electrical pulses flickering across their surfaces. Shooting them will cause the characters to react with quotes relating to them.
Element 115 was used to create the zombies as one of its side effects was the reanimation of dead cells. The zombies were to be used as super-soldiers by the Nazis. After creating them, the Nazis realized that they were uncontrollable and would lead to mankind's destruction. The Ray Gun, the Pack-a-Punch Machine, The Perk-a-Cola machines, and the Wunderwaffe DG-2 are all powered by Element 115, along with the teleporters. It would appear Element 115 can also control the zombies, as the Focusing Stone is a shrunken-down meteor that Richtofen claims will let him control the world.
- Numerous Pack-a-Punched weapons make references to Element 115. These are: the G115 Compressor, the B115 Accelerator, the G115 Generator, the MP115 Kollider, the H115 Oscillator, the R115 Resonator, the D115 Disassembler, and the L115 Isolator.
- On Shi No Numa, one of the crates in the second room on the second floor is labeled 115. The crate likely contains Element 115, indicating that some of the material was being moved from Shi No Numa for testing.
- When Woods is seen in "Executive Order", he is seen to have acquired some tattoos, one of them reading 115. Starting with SOG, this tattoo changes to read "SOG TOUGH". The tattoo still says 115 in "Payback", however.
- The clock in Der Reise has its hands at 1:15.
- In Kino der Toten, the words "The element is here" can be seen, referring to the meteor chunks that can be found scattered around the map.
- Mason is 5'11. In countries where Mason fights during the campaign (such as Vietnam), the inches comes before feet, making him 11'5.
- In the Zombies map "Five", if the player has not lowered the Defcon level and tries to enter the Pack-a-Punch room or access the broken power box, they get the message "Area Clearance 115 needed." Also, if the player tries to interact with an elevator during the Pentagon Thief round, it reads "Access Denied; Security Protocol 115."
- In "Five", when the Pentagon Thief round comes, a female voice can be heard saying "Warning, breach detected on level one/two/three" (depending on which floor the player is on). Initiating security protocol 115."
- In Call of Duty: 'Black Ops, when the player is planting a bomb in any bomb-based game mode, he is typing 115 repeatedly.
- In the loading screen of Ascension, one of the pictures in the comic shows three rockets lined up side by side, and the shadows of the rockets read "115."
- Element 115 can be seen on the moon in Der Riese, Ascension and Shangri-La.
- There is a large amount of element 115 in the map Shangri-La, as it is a mine for it.
- Element 115's use on Tank, Nikolai, and Takeo caused them to lose their memories, but they are slowly recovering them.
- In the periodic table of the elements Element 115 is Ununpentium.
- In Kino der Toten, upon getting a Monkey Bomb, Richtofen may say "You remind me of patient 13225." If one is to find the square root of 13225, they will get 115.
- Richtofen mentions that 115 is required to power the pylon in the Tower of Babble easter egg in TranZit.