Done properly, fan-made trailers can let fans live out their wildest imaginations, if only for a brief moment, to explore the question, "What if?" Fan-made trailers aren't new to the internet, especially when it relates to comic book and action movies.
For example: years ago when DC and Warner Bros first announced a Green Lantern movie was in the works, some creative soul quickly cobbled together a trailer for the movie, casting fan-favorite Nathan Fillion in the title role. Using scenes from Firefly and Green Lantern animated movies, along with some fancy graphic manipulation, the video quickly became popular (unfortunately, the movie did not).
As with our Avengers vs X-Men fan-made trailer, in-house video editor Alex Luthor is back, this time with question: "Who would protect us if the Autobots weren't around when the Decepticons invaded the planet?" Simple answer: The Avengers, of course. From Transformers (2007) to Ant-Man (2015), this trailer mashup was essentially eight years in the making, pulling scenes from fourteen movies to pit Earth's Mightiest Heroes against some of the biggest and most powerful threats they've ever faced.
Or course, fighting living robots is nothing new for The Avengers, as they had to battle with Tony Stark's greatest achievement (and greatest mistake), Ultron, as well as dispatch his horde of sentient robots in Avengers: Age of Ultron. They were able to rise above those overwhelming odds to defeat Ultron, saving the planet, but not before losing a new member of their group (Quicksilver), and not without adding several new members to their crew - Scarlet Witch and Vision. But even if all else were to fail, as Tony Stark says, "We have a Hulk."
It's highly doubtful, borderline impossible, that fans would ever get to see a crossover event like this in theaters. Even with Fox Studios and Sony both partnering up with Marvel to bring the worlds of the X-Men and Spider-Man into the MCU, the chances of Paramount bringing their multi-billion dollar 5-film franchise into the Marvel fold is highly unlikely - though an Avengers/Transformer crossover comic book event did happen during a mini-series back in 2007. Still, given the proper writers, directors and resources, one can't help but imagine the possibilities of spectacle like this taking place on the big screen.
Transformers: The Last Knight opens in U.S. theaters on June 23, 2017, followed by the Bumblebee spin-off on June 8, 2018, and Transformers 6 on June 28, 2019.
Doctor Strange opens November 4, 2016; Guardians of the Galaxy Vol. 2 – May 5, 2017; Spider-Man: Homecoming – July 7, 2017; Thor: Ragnarok – November 3, 2017; Black Panther – February 16, 2018; Avengers: Infinity War – May 4, 2018; Ant-Man and the Wasp – July 6, 2018; Captain Marvel – March 8, 2019; Untitled Avengers – May 3, 2019; and as-yet-untitled Marvel movies on July 12, 2019, and on May 1, July 10, and November 6 in 2020.