But what exactly can you expect once you unlock a Mythic? Well, Xbox CEO Asha Sharma has taken to social media to show off a clip of unlocking the Mythic in Gears of War: E-Day, which requires ticking off all 55 achievements.
As you can see from the clip below, the Mythic still shows up like a normal Xbox achievement at the bottom of the screen, but it comes with its own logo and sound clip to highlight the occasion.
You'll be able to earn Mythics in seemingly all upcoming Xbox games (although as mentioned, the feature is still limited to Insiders at the moment), and it'll also be applied retroactively to Xbox 360, Xbox One and Xbox Series games.
That means you could literally be in a position where you'll have hundreds of Mythics as soon as the feature goes live for everyone, whereas other people may only have one or two. This will all be tracked via a dedicated "Mythic Achievements" indicator on the Gaming section of your Xbox profile.
Good luck getting it in Gears E-Day though! Those achievements are both extremely difficult and a proper grind, so you should definitely feel a sense of achievement if you manage to get the Mythic in that one!