Mount Chiliad: A mysterious map at the top of Mount Chiliad in Grand Theft Auto V that is apparently connected to unlocking a jetpack in single-player among other things. A UFO will also appear if you visit the top of the mountain after 100% completion

Polybius: Rumor about a mysterious arcade game that appeared in Portland suburbs in 1981. It was highly addictive and caused serious mental health problems, while men in black would come and collect score data. Disappeared a month later, as mysteriously and suddenly as it had appeared. Seemingly a hoax created by Coinop.org owner Kurt Koller circa 2000.

Herobrine: Early Minecraft hoax where the player "Herobrine" would join single-player games, build mysterious structures, and watch the player from a distance. Thought to be the spirit of Notch's dead brother haunting the game, even though Notch does not have a dead brother. Became so popular that every Minecraft update's patch notes say that it "Removed Herobrine"

Golden Freddy: One of the FN@F animatronics. Has a small chance of showing up in the first game on the third night, and will crash the game if he kills you. Of the dead kids haunting animatronics, they have the biggest vendetta against William Afton.

L is real 2401: An interpretation of the blurry text on the star statue in Mario 64. Apparently means that if you collect 2,401 coins (supposedly every coin in the game), you will unlock Luigi. In reality, the text is either supposed to say "Eternal Star" or not mean anything, and there are less than 2,401 coins in the game (even if you count out-of-bounds coins).

Giygas fetus theory: Theory that Giygas in Earthbound is a fetus, and you have to go back in time to effectively "abort" it. Connected to one of the images of Giygas that contains the outline of a fetus. Disproven by Shigesato Itoi, saying that the fetus outline is a coincidence, and that Giygas is already fully grown in Mother.

Missingno: A glitch in Pokemon Red & Blue where you can generate a Pokemon encounter with an invalid identifier. After encountering MissingNo, the 6th item in your inventory will be increased by 128, and the Hall of Fame no longer works.

Ben Drowned: Creepypasta about a copy of Majora's Mask haunted by the spirit of Ben, a kid who drowned (duh). It originally started as a /x/ story and a few "gameplay" videos, then turned into a full-fledged ARG.

Squall is dead: Popular theory that Final Fantasy VIII character Squall dies at the end of disc 1 after being impaled by ice. The rest of the game is him dreaming. Disproven by the game's director Yoshinori Kitase, but he also said that it might be looked into as a plot point for a potential FF8 remake.

Sheng Long: Mistranslated quote from Ryu in Street Fighter 2, "You must defeat Sheng Long to stand a chance". Many thought that Sheng Long was a secret character (a theory perpetuated by gaming magazines like EGM), but in reality "Sheng Long" is just a mistranslation of "Shoryuken". When properly translated from the Japanese version of the game, Ryu's actual line is "If you cannot overcome the Shoryuken, you cannot win!" The hoax did lead to the creation of Akuma and Gouken, however.

GTA Bigfoot: Rumor that you could find Bigfoot in the forest in Grand Theft Auto: San Andreas. Completely disproven by Rockstar and dataminers, but was added to GTA 5 and Red Dead Redemption Undead Nightmare.

Mew under the truck: Mew's data was left in Pokemon Red & Blue, which led people to come up with theories on how to catch it. The most popular was that Mew was hiding under a truck in Vermillion City, and moving the truck would allow you to catch Mew. This isn't true, but you can catch Mew by following specific actions that execute specific code.

Uboa: Creepy face in Yume Nikki that has a chance of showing up if you turn off the lights in Poniko's room. Takes you to a special event if interacted with.

Madden Curse: The theory that if you're chosen to be on the cover of a Madden game, you're effectively cursed for the next NFL season, which usually comes in the form of poor performance or serious injury. While pretty consistent in the 2000s, it's been happening much less consistently in the 2010-20s.

1x1x1x1: Rumored Roblox hacker, I don't know much about this one

W.D. Gaster: Mysterious Undertale character, the predecessor to Alphys who created the CORE

HellValleySkyTrees: Strange figures in Super Mario Galaxy 2. Can be seen in Shiverburn Galaxy by going into first person and looking up and left at the top of the cliff side. Despite their name in the game's files, they are clearly not trees.

Sans=Ness: Originated from a Game Theory video saying that Sans from Undertale and Ness from Earthbound are the same character. Basically just used to make fun of MatPat at this point.

Test screen Sonic: In the Sonic CD sound test menu, putting in the code FM46 PCM12 DA25 leads to an grid of Sonic sprites with human faces, and Japanese text that translates to "Fun is infinite with SEGA Enterprises -Madzin". While "Madzin" is simply the childhood nickname of Masato Nishimura, one of the game's designers, it is pronounced the same as "Majin," which is Japanese for "Demon God" or "Devil"

Splatoon Ambience: Specifically a reference to Amb_BossCmn_FieldSE.bfstm, the audio file that plays after defeating a boss in the campaign. Contains sounds of trains, metal, and screaming. Going by the Octo expansion story, it sounds like Octolings going to the "Promised Land"

Daisy's third eye: If you look at Daisy's trophy in Super Smash Bros. Melee and manipulate the camera so it clips through the back of her hair, you can see a third eye on the back of her head.

GTA Ratman: Similar to the San Andreas Bigfoot theory, there was a theory that there was some ratman in the subways of GTA 4. The theory carried over to GTA 5, but not officially added to the game, like Bigfoot was.

Yummer: Completely out-of-place sprite found in the files of the browser game "Spongebob Saves the Day"

Deus Ex 9/11: The Manhattan skyline in Deus Ex does not include the World Trade Center because the skybox had to be cropped lower than the towers. The devs covered this up by saying that the Twin Towers were destroyed in a terrorist attack. Deus Ex was released in 2000.

Hall of Tortured Souls: An Easter Egg in Microsoft Excel 1995 that opens a small interactive first-person window with credits and photos of people who worked on the software.

Luigi's Suicide: In the phone room in Luigi's Mansion, the camera is in a different position than normal when Luigi is talking on the phone. Because of this, if lightning strikes in this camera position, it looks like Luigi's shadow is hanging.

Mother 3 Original Plot: Original plot ideas for Mother 3 when it was still being developed for the Nintendo 64 Disk Drive.

Evil Otto: Smiley-face sprite from Berzerk that shows up and instakills you if you stay in one room for too long. There are deaths related to (but not caused by) Berzerk, which created what people call "The Curse of Evil Otto"

Gyroid Faces: Glitch in the original Animal Crossing where you can swap your character's face with a Gyroid's face.

Lumoise City Ghost: Upon entering a specific floor of an abandoned office in Pokemon X&Y, the lights will flicker, a ghost girl will appear, say that you're not the one, and float away.

Renderman: Horror game in Blockland

Stop 'n' Swop: Unused feature of Banjo-Kazooie and Tooie. You would collect hidden items (mystery eggs and an ice key) to unlock things in Banjo Tooie, by swapping the cartridges. This didn't work because of the N64's hardware, but was implemented on the XBLA versions of the games (along with unlocking bonus items in Nuts & Bolts).

Saint's Row Freezer: In the Zombie Uprising mode of Saint's Row 2, you can clip out-of-bounds. This causes the game to glitch and eventually the player will run into "The Freezer," a shadowy figure that will crash the game. Apparently shows up on the Xbox 360 port and has the possibility to brick your game or the entire console.

Resident Evil COVID-19 connection: False theory that there was a research lab in Wuhan, China whose logo was just a color-inverted Umbrella Corp. logo, and they were the ones who invented COVID-19.

Battlefield V Staircase: An floating set of staircases that can be summoned on the training map. You can build up the stairs, but they will eventually crumble over time. Patched out of the game after it was discovered.

Mario Kart hostage photo: There are three images hidden in the files of Mario Kart Arcade GP: Test color bars, a photo of mascots at the 2005 Aichi Expo, and a photo of the Beslan School Hostage Crisis.

Misfortune.gb: Creepypasta about a Game Boy game that brings people misfortune and depression. Supposedly hidden in the files of many popular first party Game Boy titles.

Sad Satan: A game supposedly found on the deep web that contains disturbing imagery (which is hyped up to be a lot more disturbing than it actually is).

Killswitch: Creepypasta about an obscure Russian PC game that, upon completion, will completely delete itself.

California Speed billboard: One of the billboards in the game only contains black text on a white background that says "Sometimes God takes puppies and mommies away. And sometimes, just sometimes... I do"

Tower Unite bulletin Board: There was a bulletin board out-of-bounds on the GMOD tower map. The theory was that clicking it would take you to a different map, but the original video about this was just made to tease an "interactive horror movie" set in GMOD Tower called "The Streamer"

SCHNELLOnline: Freenet chat game a la Second Life developed by Olvin Weplanis. According to another /x/ user, "It's a reference/emulator of a creepy hidden chat room back in the day which seemed to be a cover for trafficking"

FinalDoom.wad: Does not exist. Final Doom is a game that exists, but the WAD files it uses are called TNT.wad and Plutonia.wad

Postal 2 Secret Level: This is either about the hidden Taliban base, or the "Grand Mall Reopening" in June 2016 (13 years after the game released).

GM_Construct figure: Theories about figures that show up on single-player sessions of GM_Construct.

Half-Life 2 reversed zombie audio: The random moaning of zombies, when played backwards, turn into cries for help. Theorized that Valve reversed the zombie audio because they thought that the cries of help would be too disturbing to the average player.

Runescape in NYC: Greentext about how New York City and the world of Runescape are the same, even though the comparison basically boils down to "there's a lot of cultures and a lot of beggars".

NIGHTMAR.MPG: Video file that exists on the disc of original and GOTY copies of Half-Life that is an advertisement for the Nightmare on Elm Street series on DVD. Most likely a scrapped deal between Sierra and New Line, as the video can not be accessed in the game, launcher, or installer.

Kowai Shashin: Japan-exclusive PS1 game about exorcising ghosts from haunted photos. The game is theorized to be cursed in itself.

Madcap Scout: TF2 joke creepypasta based on a bad-looking Steam Workshop entry for a Scout cosmetic called the "Madcap"

Club Penguin Silhouettes: Silhouettes of penguins can be found in some areas of Club Penguin Island. Originally added in 2008 to promote the upcoming addition of ninjas, and if you click them, they would move around and disappear. They were just never fully removed after ninjas were added.

Nexialist: Worlds.com player rumored to have started an in-game cult

Every copy of SM64 is personalized: Recent theory about Super Mario 64 containing experimental AI that subtly adapts the game for the specific player. Used to explain the Mandela Effect people have about the game.

Duke Nukem Hot Dog: The only thing I can find about this is the Hot Dog mission from the Duke Nukem Forever level "Duke Burger"

Kanye Quest: RPG Maker game where you play as Kanye West in the future. Years after the game released, people discovered a hidden area that is supposedly used as a recruitment tool for the Ascensionism cult. There's a prompt to put in your address in this secret area, but no one who had to the balls to do it actually had anything happen to them.

Tony Hawk's Underground 2 Red Face: Texture of a creepy red face located out-of-bounds on the Santa Cruz map.

GBA SP Blue Edition: Joke creepypasta created by Oney about how stealing is bad.

Girl Games: Flash game website that promotes those disgusting Disney princess surgery games

Witcher 3 female ghost: I'm not sure what this is specifically about, but I'm guessing it's about the "Last Rites" mission. In it, an old woman tells you to bring her wedding ring to her husband's gravestone. When you return, the woman's granddaughter says that the woman you talked to died years ago, and Geralt concludes that he was talking to a ghost.

Tomb Raider secret temple: Out-of-bounds building found in Tomb Raider: The Last Revelation. Just a giant cube with a single texture of a stone sculpture on every surface.

"Who are you running from?": On the Game Boy Camera "shoot" menu, selecting the "run" option will sometimes come up with a creepy, edited picture of a person while text at the top says "who are you running from?"

"That evil farming game": A Harvest-Moon like game where the twist is that the game starts with you murdering your wife, and you have to hide her body from police. Multiple Redditors have talked about playing the game in the past, and it apparently either came from a PC gaming magazine demo disc, or from an online game-downloading website.

Talking Angela Pedophiles: Facebook hoax that Talking Angela and other "Talking" apps were run by pedophiles to gain personal information about children (and also that you could see the offending pedophiles in the reflection of Angela's eyes). Actually made its way into mainstream news, so I have no idea why it's this far down on the iceberg.

Waluigi Cult: Waluigi has a cult following and a lot of memes that deify him

NBA Jam Petrovic: When NBA Jam first released in arcades, it had the tendency to randomly play the "Petrovic" voice line. Since Petrovic had died between the game's development and release, many believed that he was now haunting arcade cabinets of the game. Later releases of the arcade game fixed this issue, and Petrovic was removed entirely from the home console version.

Camdrome: Video game/ARG about hacking webcams and stalking people. It had a few demos at MAGFest, but nothing has been said since 2017.

Helious.exe: Creepypasta about a DOS game made by Sean Puckett after aliens left the Helious files on Sean's computer.

Doom is predictive programming for CERN: People have crazy theories about particle accelerators, and I guess "it'll open a portal to hell" is one of them.

Video games created to promote drugs: ???

Games aren't real: ???

Epstein created Fortnite: Were Donald Mustard or Tim Sweeny found on the flight logs?

Anomaly 1622: One of many characters in a series of various amateur animations of Minecraft "anomalies" fighting each other

Steam Amnesia Sounds: Steam's music player sometimes detects sounds from Amnesia as "music" even though it's just sound effects.

Nintendo is connected to the Yakuza: Back when Nintendo was a hanafuda card company, they were one of the Yakuza's main suppliers.

Snuff games: Like snuff films, these are games that depict the real deaths of people made solely for "entertainment"

The first game: Debate on what can be considered "the first video game"

Pong 1/24/1970 Build (DO NOT RESEARCH): Seemingly just a reference to the "1995/07/29 Build (DO NOT RESEARCH)" on the Mario 64 conspiracy iceberg. The only notable thing that happened on January 1, 1970 was the birth of Matthew Lillard.