[UPDATE] In a Reddit post (via PC Gamer), Team Guru outlined the "no shortcuts, no cheating, legit way" to access GTA Online's alien mission.

　　To trigger the mission, you apparently have to complete 601 Gunrunning sales, and then begin a supply run between 21:00 and 23:00 for the in-game clock. "Yep, it really is that simple. But considering the amount of time it takes to do 600 sales means that this isn't an easy thing to achieve," reads a line from the Reddit post.

　　Additionally, the alien mission will reportedly only trigger once.

　　The original story is below.

　　GTA Online's Gunrunning update, which was released in June, apparently contained clues about a secret alien mission, which modders have now unlocked and played. As Kotaku reports, the Gunrunning update's code suggested that there might be a UFO crash site nearby the Zancudo military base. Now, the folks behind a modding group called Team Guru have found a way to unlock the mission, which you can see below.

　　As you can see, it's not the most thrilling of missions. At least in the state it's in now, the player comes upon a massive, crashed alien ship, with dead scientists in a swamp. There is an alien egg out in the open that the player acquires, at which point a few ETs spawn and must be dealt with. Then the player drives the egg to a bunker to finish the mission. Bear in mind that this mission, if it's real at all, might not be finished, as it was discovered in the game's code and before Rockstar made any mention of it.

　　"Much hard work, two weeks of sleepless nights, and years of research have gone into bringing this to you guys," Team Guru said in a Reddit post. "What does this mean for the mystery?? Who knows, we still don't have the undamaged ship being used, yet!!"

　　This isn't the first time aliens are in GTA V. There is a sequence in GTA V's single-player mode where Michael does drugs and sees aliens that he has to gun down with a huge chain gun. The new GTA Online alien mission could be the signal of grander plans.

　　The newest GTA Online is out now, adding a number of 4th of July-themed items, as well as a new mode and a number of discounts. For lots more on the update, check out GameSpot's full breakdown of everything it comes with.

　　GTA V is one of the most successful games ever. Recently, the open-world game passed 80 million copies shipped, and it continues to sell well.