So in case you haven't heard yet, it's been a long running theory in the Rick and Morty and Gravity Falls fandoms that the two popular animated shows are in fact related. The show's creators Justin Roiland (Rick and Morty) and Alex Hirsch (Gravity Falls) are close friends, having worked together in the same Disney Channel office earlier in their careers.
Justin Roiland who voices the titular Rick and Morty characters and Lemongrab in Adventure Time also plays Blendin Blandin and Bobby Renzobb on Hirsch's Gravity Falls, whilst Hirsch has guest-starred as Toby Matthews in Rick and Morty S02E07 Big Trouble In Little Sanchez.
The theory that the two universes are related however extends beyond the friendship of their creators and the general sci-fi "weirdness" that forms the backbone of each show's mythology, as eagle eyed fans have noticed direct references passed between the two.
Perhaps the most prevalent of these is the one highlighted in the video below, where Grunkle Stan in an episode of Gravity Falls looses his notepad and mug through a portal he's opened, only for the items to fall out the other side in the background of an episode of Rick and Morty.
There's also been a visual reference to Gravity Falls' dream demon antagonist Bill Cipher, which appeared in the same Rick and Morty episode that Alex Hirsch guest starred in: Big Trouble In Little Sanchez.
Naturally these connections have led to rampant speculation that the two shows exist in the same universe, particularly the portal example, and so discussions of crossover potential abound.
In a recent Entertainment Weekly interview Alex Hirsch was asked about the potential for a crossover or something of the like to happen between the two shows and whilst his response didn't exactly clarify much he did say that the crossover elements between the two were put in to tease and "freak out" fans:
"[Justin Roiland and I] both dreamed one day of having our own weird TV shows, and we would talk about ways in which we would childishly abuse this power. For some reason, the universe has blessed us with our mad wishes, and it occurred to us — let’s start doing things that nobody else does, that maybe you’re not supposed to do. We started putting little Easter Eggs in our shows that sort of connected the two. Our motivation for that is primarily to freak people out and blow their minds. The impression of a grand brilliant design is probably more something that the fans have invented."
Oh, so maybe there's not going to be that epic Gravity Falls/Rick and Morty crossover episode that fans had hoped for after all?
"I remember when I was a kid, whenever you’d see cartoons cross over with each other, it always ranged from a delightful, magical surprise to a cynical, annoying cash grab. So far, we’ve found that these little winking nods between our shows strike the right balance. I can’t say whether or not there will be more, but I can say that we like to confuse and amuse people so who the hell knows."
Both Roiland and Hirsch have always embodied a certain off-the-wall, tongue-in-cheek humour about their shows, and whilst Adult Swim's Rick and Morty certainly deals in more R-rated humour than the Disney Channel's Gravity Falls there is a certain disconnected weirdness in their tone which strikes a cord between the two, so there's no real surprise here that fans have drawn similarities between them.
Whilst Hirsch says they don't have any specific crossover plans, he did rule anything out either; and as anyone who is familiar with Roiland and Hirsch's work will know anything goes, so who knows what we'll see from them in the future. For now it looks like we're just going ot have to make do with keeping an eye out for Easter Eggs. At least there's always Hirsch's Rick/Stan whiteboard Vine...
Related: Will Rick & Morty Season 3 Explore The Backstory Of Dan Harmon's Favourite Character?; Rick and Morty Season 3, And The Back To The Future Parody That Started It All; Rick and Morty Season 3 Creators Tease A Return To Previous Cliffhangers And Characters.