What is the multiverse and why does it seem to be popping up everywhere in pop culture right about now?
In film, you've got the MCU (Marvel Cinematic Universe) and the still-just-about-alive DCEU (DC extended universe).
Regarding Marvel, thanks to 'Avengers: Endgame', a multitude of timelines and universes have been established. It means that series like 'Loki' (in which the character is alive, though he's dead in the main story line) and the enigmatic 'Wandavision' can exist.
There's much excitement as well for movie sequels like 'Spider-Man 3' and 'Doctor Strange in the Multiverse of Madness', which will deep dive into the sci-fi trope.
Moreover, before the Marvel Disney+ series came into being, we had the "Arrowverse", encompassing 'Arrow', 'The Flash', 'Supergirl' and more.
We'll also see DC explore the concept of the multiverse in the upcoming 'The Flash.'
It's not just movie giants Disney and Warner Bros. that are exploiting multiverses for all their possibilities either.
Who could forget animated feature 'Spider-Man: Into the Spider-Verse', which proved a massive hit for Sony?
Heck, even the latest season of Netflix series 'Chilling Adventures of Sabrina' started exploring the concept of multiple universes.
It's worth noting though that the multiverse is not new or particular to this surreal epoch we're living in.
Consider shows like 'Doctor Who' and 'Star Trek', or the establishment of multiple universes in comic books.
It is a concept that has been explored in games series such as 'Super Smash Bros', and books like 'The Chronicles of Narnia'.
But while it isn't unique to contemporary times, there are reasons why we're seeing the multiverse now more than ever.
Nostalgia has become a more bankable factor in TV and film-making than ever before, and the multiverse is leaning into it with finesse.
The recent final season of 'Chilling Adventures of Sabrina' saw the actors from 'Sabrina the Teenage Witch', Beth Broderick and Caroline Rhea, reprise their roles as Aunt Zelda and Hilda, to the delight of fans.
Additionally, the new 'Flash' movie could see Michael Keaton reprise his role as Batman from the 1989 film and its sequel.
If the numerous movie cast reunions over last year, and the excitement around upcoming sequels like 'Coming 2 America', 'Hocus Pocus 2' and 'Sister Act 3' has taught us anything, it's that we're fools for nostalgia.
2. Expansion of characters
The multiverse allows for not just the return of characters, as is the case for 'The Flash' and 'Spider-Man 3' (which sees a whole host of characters from previous Spidey movies join Tom Holland) it also allows for the expansion of well-known, beloved characters.
'Spider-Man: Into the Spider-Verse' is a particularly good example here. It took a well-established and widely known character property and delivered something modern, unexpected and vibrant with it. It couldn't have been done without the idea of there being multiple universes within the franchise.
The upcoming 'Loki', meanwhile, will give a popular supporting character the chance to shine and have his own story.
We're always saying that Hollywood is running out of ideas and leaning on remakes too much.
But the great thing about science fiction as a genre is the imaginative and creative potential it has, and the multiverse is a trope full of potential.
The likes of 'Rick and Morty' show how completely mad and off-the-walls you can go with multiple universes if you're daring enough.
The Adultswim series has shown its potential for humour as well as darkness, and generally thought-provoking concepts.
Consider 'Wandavision' too and its utilisation (from what we've seen so far) of multiple decades and styles in its storytelling.
We may very well get to the point where the multiverse has been overdone. But we're not quite there yet.
4. Time travel
There's something about time travel as a device in movies that audiences just love.
Aside from 'Back to the Future', there are plenty of examples of it, spanning 'Groundhog Day', 'Terminator 2', 'Donnie Darko' and more.
The multiverse is both a result of time travel oftentimes (see DC and Marvel), but it is also a means of using the popular storytelling device.
5. Establishing connections
Lastly, simply put, there's fun and satisfaction in making connections between universes, seeing the old meet the new, such as old Spock meeting new Spock in 'Star Trek', or the different Spider-Mans meeting one another in 'Into the Spider-Verse' (or indeed in the upcoming 'Spider-Man: Far from Home' sequel).
As humans, we like organisation and putting things into groups.
Perhaps it sounds a bit dramatic to say that the multiverse, in this way (and from the perspective of its nostalgic and creative properties), taps into what makes us human. But maybe that's what's owing to its popularity now more than ever.