UPDATE 15/11/2016 8.51pm: A new report suggests the Ubisoft sci-fi game teased within Watch Dogs 2 is real. There's only one problem: it may never come out.
Kotaku sources have verified the in-game trailer is real, and for a space exploration game codenamed Pioneer. However, Pioneer is being "retooled" and is unlikely to be announced in the near future as Ubisoft had initially planned.
"When they decided to make the easter egg in Watch Dogs 2 they didn't know it was going to be like this so it's a bit awkward," one of the sources said. The other noted that the original plan was for Ubisoft to reveal Pioneer in 2017.
This wouldn't be the first time Ubisoft has teased a game only for it to go underground. The publisher notoriously released a Beyond Good & Evil 2 teaser in 2008, then did not confirm the game as in development for another eight years.
ORIGINAL STORY 14/11/2016 10.01am: Watch Dogs 2 can get very meta - very, very meta. We'll go into this more when the game's review embargo has expired.
But footage of one particularly eye-opening sequence has already hit the 'net thanks to those with early copies - and it sees you uncovering a new Ubisoft game. Maybe.
A fictional version of Ubisoft San Francisco exists in Watch Dogs 2 for you to explore and hack into.
There's even a mission which tasks you with stealing an E3 teaser from the company's servers.
Nab the footage and it turns out to be a new sci-fi spaceships game with the colour palette of No Man's Sky:
So far, so meta. Except... there's also an ex-Ubisoft developer who says the game fits with something in development two years ago when he was still at the company.
"Oh, huh, finally this is starting to get teased," the ex-Ubisoft dev wrote on NeoGAF. "Knew very little about it just before I left Ubi over two years ago and never actually saw any in-game stuff. Interesting!
"Pretty sure it's real, like I said, I only heard rumblings of a big space game as they keep stuff on tight lockdown even between studios, so my knowledge ends at that sadly."
The whole thing may just be a ruse, or it may deliberately tally with a game Ubisoft is creating.
The mission even nods to other Ubisoft games in development - including an Assassin's Creed set in Egypt, which is almost certainly a thing.
Want to play the mission for yourself? Our Ubistolen side mission page can help point you in the right direction, and our Watch Dogs 2 walkthrough and guide can assist with other parts of the game too.