GTA 5 is an extremely adaptable game in the sense that it just works so damn well in conjuncture with so many other popular and well established franchises that fans cannot help but create crossover content. What's more, the blockbuster franchise pulls this off while retaining a personality of its own along the way.
Thanks to mods and the Rockstar Editor, the game's built-in video editing software, the creation of such cross-over content has been made much easier and more accessible. The creation of fan videos is no longer reserved for an inner circle who knew their way around gameplay capture software and editing suites.
Now, anyone could record and edit their videos right in GTA V, plus with mods thrown in, it was easier to create more authentic adaptations. This has spawned a massive fan video community churning out an immense quantity of content, much of which is actually pretty damn good.