Black Mirror is an anthology series in which each episode is not connected to the others in terms of plot or characters. However, there is the theory that all the stories can coexist in the same universe. Some even say it's not just a theory, that's it's confirmed based on comments creator Charlie Brooker has said in the past.
If you have watched all of Black Mirror, then you should recognize that this is a pretty hefty theory. All episodes focus on how a single piece of technology can change society and it's rules. For all that tech to exist at once is a lot to take in. True or not, there are little Easter Eggs all over the series that show connections to other episodes. Here is what we've found.
In season 2, episode 3 of Black Mirror we get an episode called "The Waldo Moment." The episode explored how a comedian who does satire behind the face of a fictional character gets caught up in a political race. It came out in 2013 and was known as one of the series' lesser episodes, until the 2016 North American election made everyone re-examine it with a new fascination.
In one city-scape scene there is an ad for Abi Khan. She was the poor girl from the second episode "Fifteen Million Merits" who was pressured into being a reality TV star. So apparently, she exists in this episode's world.
This was not a forgettable pregnancy test. With most of Black Mirror's episodes taking place in the future, they implemented new technology in the background as well as the forefront of each episode. Such tech included a cute pregnancy test that shows a picture of a happy moving baby if the user is pregnant.
The first time this test was seen was in the season two's episode, "Be Right Back," and again in "White Christmas."
The unfortunate Prime Minister from the very first episode of the series is hidden in various episodes. In season three's "Nosedive" episode, there is a status from him saying that he got kicked out of a zoo "again." In the episode "Shut up and Dance," a Tweet mentions Callow getting a divorce and the same news is shown in "White Christmas" except we see it backwards. In the episode "Hated in the Nation" it shows his name trending on Twitter. In the episode "Black Museum," we see news that Callow has married a pig on a tablet.
From the episode "Hated in the Nation," the Granular Company were the creators of drone bees. By the end of their episode, their bees were hacked to kill tons of people. However, it's possible that the company exists within other Black Mirror episodes. Perhaps bees are not the only creation we will see of theirs.
Their company name is shown at the bottom left part of a magazine from another episode, "Playtest."
"The Black Museum" episode basically had a collection of items from a bunch of other Black Mirror episodes. The displays included a drone bee from "Hated in the Nation," a picture of Victoria Skillane from "White Bear," and the game from "Playtest" to just name a few. Besides those items, headlines also play a big part. These headlines include "Arkangel system pulled from stores" which is a reference to the episode "Arkangel," "Shou Saito trial continues" which is a reference to the episode "Playtest," and "Waldo Politician makes waves in Mexico" from the episode "The Waldo Moment."
The song from the second episode of Black Mirror, "Anyone Who Knows What Love Is (Will Understand)" makes numerous appearances in various episodes. It was sung by Abi Khan, and it's a pretty haunting one especially since it was the last thing she did before she was drugged and taken away by the reality TV industry.
It plays in the episode "Crocodile" a number of times. It's also part of a karaoke track in the episode, "White Christmas." In the episode "Men Against Fire," the character, Raiman sings the song.
Due to the disturbing fame of the cartoon comedian, Waldo, it would be easy to believe his face would be everywhere. Shared universe or not, he is in episodes other than his own. It's rather funny since we are literally asking ourselves "Where's Waldo?" when it comes to these Easter Eggs.
In "Shut Up and Dance," Kenny has a Waldo sticker on his laptop and another similar sticker is seen in "Hated in the Nation." In "White Christmas," we see Waldo on the television for a moment while Joe if flipping channels. In "Arkangel," we see a Waldo lunchbox.
After Clark puts in the ignition code in the episode, "Metalhead," a bunch of text pops up that references many episodes of Black Mirror. It's small, so it's easy to miss. However fans closed in on the text and shared what they found online.
The various tests read, "LOADED: \BMS1E1.drivers.tna.pigpoke" (reference to episode "The National Anthem"), "LOADED: \BMS1E2.drivers.15mm.bing.abi" ("Fifteen Million Merits"), "LOADED: \BMS2E1.drivers.brb.attic" ("Be Right Back"), "LOADED: \BMS2E2.drivers.white.bear" ("White Bear"), "LOADED: \BMS2E4.drivers.white.xmas" ("White Christmas"), and "LOADED: \BMS1E3.drivers.tehoy.men" ("The Entire History of You").
Victoria Skillane was the main character in the episode "White Bear," a story which revolves around a criminal who gets punished for her crime over and over again for public entertainment. Her name is seen and mentioned in episodes apart from her own.
In "Shut Up and Dance," we see on a webpage that her latest appeal was rejected by court. In "Hated in the Nation," her name is seen as one of the names in the "#DeathTo" Twitter hashtag. In that same episode, Blue mentioned that she previously worked on the Ian Rannoch case, which Victoria Skillane is was tied to in her episode.
UKN is a fictional media network that appears in various Black Mirror episodes. It was featured a ton in "The National Anthem." In "Be Right Back," they were the ones who announced the scientific breakthrough of creating fake human skin. In "White Bear," they are the news that reports on Victoria's involvement with the Ian Rannoch case. They also cover the election in the episode, "The Waldo Moment."
In "White Christmas" it's the UKN that covers the Kirkconnel rail crash that kills Joe's ex-girlfriend. In season three, the media network reports on the #DeathTo hashtag in "Hated in the Nation."