'Stranger Things' is one of the best inter-dimensional stories of the year.

Are you ready to step into the multiverse?

At its core, multiverse theory in physics is the assumption that any number of mirrored realities might be layered atop our own. Every choice we make creates a singular timeline that exists apart from all others where different choices were made with infinite variation; which is great news for science fiction fans. More and more, theories of alternate dimensions and mirror realities permeate through some of the most popular fictional stories around, whether there are speedster superheroes involved or not. DC Comics, Marvel Comics, Star Trek, Doctor Who, Rick and Morty, The Flash — if there’s a franchise with sci-fi elements, you can bet that its characters have stepped into an alternate reality at some point.

In The CW’s Arrowverse, there are 53 different Earths, and Barry Allen has stepped foot in five of them; his team member Cisco, aka Vibe, has probably been to even more. Over on Adult Swim, Dan Harmon and Justin Roiland’s widely beloved Rick and Morty showcases an infinite number of alternate realities almost as often as it does the far reaches of the universe via space travel. And who can forget everyone’s favorite Eggo-loving telekinetic Eleven, who on Netflix’s Stranger Things has been to the Upside Down and back again.

These represent some of the most popular stories in genre fiction these days, and an important part of these stories involves bringing these characters to new and strange worlds that are sometimes all too familiar.

Here are 10 of the best inter-dimensional stories of 2017:

10. Pokémon Ultra Sun & Ultra Moon

The latest generation of main Pokémon games has gone all-in on a kind of universal convergence with what they call “Ultra Wormholes.” Originally introduced in a minor capacity in Sun and Moon, these Wormholes allowed Ultra Beasts — extradimensional Pokémon originating from Ultra Space — to enter the Alola Region. They’re basically superpowered extraterrestrial beings that originate in a dimension that far transcends our own.

In Ultra Sun and Ultra Moon, these insane sci-fi concepts are explored a bit further in the narrative. When you travel through Ultra Wormholes, you can explore different worlds and capture Legendary Pokémon from just about any previous game.

One particular world is the “Ultra Megapolis,” which has had its light stolen by the Pokémon Necrozma:

You can even go to Ultra Megapolis.
You can even go to Ultra Megapolis.

“Within this world, wrapped in darkness, a mysterious tower-like building shines with brilliant light.” It’s pretty dark stuff for a Pokémon game, and even though the execution of it narratively is fairly mundane, the whole concept is a welcome and refreshing change of pace for the series.

Jason Isaacs as Captain Lorca in 'Star Trek: Discovery'.
Jason Isaacs as Captain Lorca in 'Star Trek: Discovery'.

9. “Into the Forest I Go” — Star Trek: Discovery

Star Trek has a long history with mirror reality and alternate timelines, and while CBS’s latest foray into the world of Trek originally promised to show a stretch of time period that occurs just before the Original Series, the mid-season finale in November — “Into the Forest I Go” — teased what might just be an alternate universe.

At the end of an incomplete mycelium jump, the know-it-all Saru declared, “Captain, I’m afraid I don’t know where we are,” which should be impossible. That was the cliffhanger we were left with, the implicated that the Discovery had accidentally wound up in one of the alternate realities that Lorca and Stamets were talking about earlier in the episode.

We’ve known since September that at least one Mirror Universe episode was coming, as it was confirmed by Jonathan Frakes. This universe has been depicted before on Trek.

Will this be the same Mirror Universe? A different one altogether? Maybe Star Trek: Discovery has been a mirror universe all along?

These are the kinds of plot twists that make stories about the multiverse some of the coolest around.

8. Super Mario Odyssey

Everybody loves the little Italian plumber that’s been saving his princess girlfriend from dinosaur turtles for decades, but his latest adventure on the Nintendo Switch claims a high spot on almost everyone’s “Best of 2017 Video Games” lists, and with good reason.

There’s something undeniably hilarious about seeing short, pudgy Mario with his goofy mustache traipsing about in a world that, for all intents and purposes, looks exactly like the real world. We get as much in Super Mario Odyssy and so much more.

In Odyssey, a spirit named Cappy takes over Mario’s hat, allowing the plumber to possess various beings across the various worlds in the game.

"Oh-a hello! Eets a ME! Maaariooo!"
"Oh-a hello! Eets a ME! Maaariooo!"

The franchise has always dealt in “Worlds” in a colorful, fun-loving, and casual way. But this, alongside the likes of Super Mario Galaxy, feels a little bit more sci-fi in a really cool way.

For awhile, Josh loves living in the place of his douchey, but super-rich doppelganger.
For awhile, Josh loves living in the place of his douchey, but super-rich doppelganger.

7. Future Man

I’ve written at great length about this before, but Future Man brilliantly — and comedically — dramatizes how time travel forward and backward essentially represents a certain kind of interdimensional travel.

Because of principles and paradoxes like causation, pre-determination, and the butterfly effect, even small changes to the timeline can have massive implications on the future. Therefore, the time traveler essentially becomes unmoored in time, unable to ever truly return to his or her “home” dimension. It’s something that the show’s core three characters have to grapple with throughout the first season, which is some heavy stuff considering how many dick and barf jokes are littered throughout Future Man.

The show’s at its best when the protagonist Josh earnestly warns an important person in the past about what they’ll do in the future, only for Josh to go back to the “present” and come face-to-face with his own douchey doppelganger in a world that he inadvertently made worse.

When we see time travel in various other narratives, the implications are rarely explored to this exhaustive degree, and Future Man does just that and flourishes while doing so.

6. It

Stephen King’s original story gave us all nightmares and coulrophobia, but It is so much more than just clown slasher horror. Deep underneath King’s narratives often lurks the underlying Lovecraftian themes of the cosmic, transdimensional horror within a multiverse. (He explores it much further in his Dark Tower series.)

Sure, “It” often takes the form of Pennywise the Dancing Clown for kicks, but the creature is actually a shapeshifting entity from an unknown realm or dimension outside the regions of space itself. All good interdimensional fiction reminds us that in an expanding universe, an individual person is infinitesimally tiny by comparison.

In this year’s well-received and exciting live-action film adaptation of the story, the group of kids join together as the Losers’ Club to fend off the demonic entity together. It isn’t until the final act that we really come to understand the scope of this creatures power, but as the paranormal horrors unfold, we ultimately come to realize that it all comes from a dimension far outside the scope of our understanding.

"Hiya Georgie!"
"Hiya Georgie!"
This is only a sampling of the heroes features in "Crisis on Earth-X."
This is only a sampling of the heroes features in "Crisis on Earth-X."

5. “Crisis on Earth-X”

Unsurprisingly, the best thing to come from live-action storytelling with DC Comics characters came on The CW instead of the DCEU. This year’s Arrowverse crossover offered a spectacular interdimensional team-up with a dizzying array of superheroes that felt more like Infinity War than it did Justice League, and it was definitely way better than the latter.

In “Crisis on Earth-X,” The Flash’s wedding is crashed by Nazis from Earth-X, an alternate reality where the Nazis won World War II and, in the present day, Oliver Queen is the Fuhrer with Kara Danvers, aka Overgirl, as his wife. So basically, Green Arrow and Supergirl are Nazi overlords with an entire conquered world at their back.

The Arrowverse is fond of these interdimensional romps with villainous doppelgangers — we’ve seen it happen often on The Flash and a lot this season on Arrow with Earth-2 Laurel Lance — but never before has it pulled off one of this scope so damn well.

We get narrative development for characters on all four shows — Arrow, The Flash, Legends of Tomorrow, and Supergirl — while generally just speaking having an awesomely fun time.

4. The Lego Batman Movie

Lego Batman had his hilarious first role in The Lego Movie (2014), which itself spawn something of a Lego Multiverse with a dizzying array of characters from different universes. While The Lego Batman Movie focuses primarily on characters from Gotham City and the broader DC Universe, the folks at Warner Bros. own SO many different franchises, so why not throw a ton of them together?

Spoiler alert One twist from the movie happens when the Joker gets himself sent to the Phantom Zone, an alternate dimension prison where tons of villains are kept. While there, he eets a TON of villains: Voldemort, the Eye of Sauron, Godzilla, King Kong, Daleks, Gremlins, Jurassic Park dinosaurs, the shark from Jaws, and the bad Agents from The Matrix.

This is just further proof that the Lego Multiverse is one that’s going to stick around for a long time and keep delivering more and more movies for audiences that love some blocky fun.

'The Lego Batman Movie' has a LOT of characters, but it brings in far more than just the DC Comics universe.
'The Lego Batman Movie' has a LOT of characters, but it brings in far more than just the DC Comics universe.
Eleven uses her powers to close the breach to the Upside Down at Hawkins Lab.
Eleven uses her powers to close the breach to the Upside Down at Hawkins Lab.

3. Stranger Things 2

Everything from Netflix’s dark sci-fi darling Stranger Things is an absolute delight, from its hardcore ‘80s nostalgia to its heady notions of the Upside Down, a dark and horrify dimension that mirrors our own. In both seasons of Stranger Things, characters find themselves either trapped in the Upside Down, plagued by visions from it, or otherwise hunted by horrific monsters from that nether realm.

Eleven gained her powers from a secret government program, and while training her to remotely assassinate people anywhere in the world, they inadvertently ripped open a rift to the Upside Down. In Season 2 — which released on October — some sort of massive hive mind entity they call the Shadow Monster possesses the same young boy that spent most of Season 1 trapped in the Upside Down.

But the rift causes far more problems for the folks of Hawkins, Indiana, and it’s up to the group of youngsters and a few adults to close the breach and stop the problems from spreading. If the teaser at the end of the season is any indication, however, then it’s not the last we’ve seen of the mystery Shadow Monster.

2. Thor: Ragnarok

The Marvel Cinematic Universe has a complicated relationship with dimensions, realms, and other realities that’s only going to get more complicated when Avengers: Infinity War comes out and Thanos inevitably gets his hands on the “Reality Stone” — which could theoretically could allow him to create a new universe or wipe out the one we all know, love, and have spent hundreds of dollars at the movie theater to watch.

Taika Waititi’s Thor: Ragnarok is not only one of the best MCU movies ever, but it’s one of the best films of 2017. Thor’s journeys have always dabbled the most in various realities — or as he likes to call them “realms.”

In Ragnarok, Thor’s sister escapes from some interdimensional prison and threatens to destroy all of Asgard. The tale becomes something of a cosmic buddy-cop bromance between Thor and Hulk on the gladiatorial planet Sakaar before they’re able to sort things out.

But really, where exactly was Hela imprisoned? And how is Asgard even cosmically possible if it exists as a kind of massive disc in space? The previous two Thor movies felt mystical in their tone, but Ragnarok takes things to the cosmic extreme, making it finally feel like it belongs in the same universe as the Guardians of the Galaxy.

Thor and Hulk share a moment in 'Thor: Ragnarok'.
Thor and Hulk share a moment in 'Thor: Ragnarok'.
Candidate Morty runs for office with a staff full of ... Mortys.
Candidate Morty runs for office with a staff full of ... Mortys.

1. “The Ricklantis Mixup: Tales From the Citadel” — Rick and Morty

Honestly, this particular episode of Rick and Morty might be the single best episode of television in all of 2017. For a show that’s already at the forefront of the zeitgeist to do something this bold and different from its usual format while still thriving is just damn impressive. “Tales From the Citadel” manages to thoroughly dramatize the insane multitude of universes the show contains by its conceit while also bringing back Rick and Morty’s best villain.

In this episode, we get a series of vignettes interwoven on the Citadel, the massive floating space station where Ricks and Mortys converge to build their own civilization, one that was devastated by the show’s leading duo in the Season 3 premiere.

We see an insane number of Ricks and Mortys going about their lives just trying to survive. There’s a group of Mortys in a Hogwarts-esque school for wayward Mortys, a disgruntled factory worker Rick, and even a Morty running for public office that’s more nefarious than he seems.

This may not have been this season’s finale, but it was the standout story of the year and deserves top marks on this list and a truly stellar half-hour of animation.

Here’s more talk about Evil Morty and why “Tales From the Citadel” was amazing: