This feature was originally published on CVG, but the mystery remains unsolved. We present all the evidence here so that we can pick up the thread in the PC edition and crack this once and for all.

Forget Big Foot, Leatherface and ghost cars. Grand Theft Auto 5 might be home to the biggest video game conspiracy of all time, with a tantalising reward for its solution. This needs some explanation.

The following article contains mild Easter egg spoilers. Please contact us for credit if we have used any of your map images—with special thanks to GTA Forums.

Throughout the game's life, GTA fans have been flexing their detective skills on sub-Reddits and forum threads, debating pictures of in-game graffiti, curious murals and 'phantom' UFO sightings. Bottom line: the Internet hive mind thinks that 100% completing GTA 5—a task that takes 50 to 60 hours—is when the race for its ultimate prize begins.

The reward is unconfirmed, but (MILD SPOILERS AHEAD) there are obvious clues. GTA 5's grandest conspiracy centres on a cave painting-style mural at the top of Mt Chiliad's cable car station. It's barely hidden, which suggests Rockstar wants people to find it and get involved.

The Mount Chiliad mural

The mural features a glowing eye and a series of connected boxes marked with an X. At the bottom of the flowchart structure are three boxes showing (what looks like) a UFO, an egg and a man with a jetpack. The consensus is that these are the prizes for solving the puzzle: a UFO you can pilot, a jet pack (like Grand Theft Auto: San Andreas' greatest gadget) and, er, an egg. This is the weird bit, with some suggesting you'll unlock a dinosaur (unlikely, but you can see a T-Rex shadow on one face of Mt Chiliad)—or, more likely, some kind of alien egg.

The glowing eye and lightning emerging from the sides suggest a link to the Illuminati (arguably the real world's greatest conspiracy theory), variously linked to major religions, global political control, finance and—of course—aliens. Franklin's house contains an Illuminati-style poster, and there are similar symbols all over Los Santos; the significance of which is still being debated.

Initially, it was felt that the mural represented a cross section of Mt Chilliad, with each box representing a hidden location. However, compelling evidence suggests the mural should be overlaid on the game map, with the shining eye on top of the north coast—the exact placement is still being debated. See below.

Next up: a case for Mulder and Scully.