What exactly is a shared universe in film? It’s basically when unrelated movies share certain characters and exist within the same world. It combines two or more standalone films, sometimes from different writers/filmmakers. We see the concept of a shared universe in many forms of media: movies, comic books, television, and literature. All the films below could exist in the same universe. Don't believe it? There's plenty of evidence!
It’s important to note the idea of a shared universe can just act as a very small part of a film. It may be just a winking cameo, like when Dr. Raymond Stantz (Dan Aykroyd) from Ghostbusters, drops in for a quick scene in Casper.
Other times, the concept of a same universe theory is the groundwork for an entire network of movies. You've likely heard of the Marvel Cinematic Universe, combining the forces of many different superheroes. But there are also a few post-modern directors that elicit rabid same universe fan theory. The same universe theory allows us to loosely link all of Quentin Tarantino’s movies, his canon of work is called Tarantino Universe. Sometimes his characters are related, sometimes they work together, and sometimes they just go to the movies together. Some of the Tarantino connections are stronger than others, and the ones listed below are totally cut and dry.
This shared universe makes sense since both films center around ghosts. The 1984 comedy classic features three parapsychology professors who set up shop as ghost removal professionals. In 1995's Casper, an abandoned house is littered with three not-so-nice ghosts and their nephew Casper, "the friendly ghost." The house's owner calls upon an expert in ghost removal and who shows up?
Dr. Raymond Stantz (Dan Aykroyd) dressed in complete ghostbuster's apparel enters the picture for a brief cameo. However, he doesn't have his full crew. Casper's three menacing uncles prove to be too much for Ray. After his ghost defeat, he races out of the house and informs the owner, "Who you gonna call? Someone else."
Independent film director Kevin Smith is from the Garden State of New Jersey. Most of his films exist in the same universe, called the View Askewniverse, which is named after Smith's production company, View Askew.
Films in this universe include Clerks, Mallrats, Chasing Amy, Dogma, Jay and Silent Bob Strike Back, and Clerks 2. Those movies all take place in the New Jersey and New York area and share several of the same characters and themes. The View Askewniverse also consists of comics, an animated TV series, and several of Smith's short films. Jay and Silent Bob appear in most all of the films in the View Askewniverse.
We know for sure that Vincent Vega from Pulp Fiction and the sadistic Vic Vega (AKA Mr. Blonde) from Reservoir Dogs are brothers. In fact, director Quentin Tarantino even talked about his plans for both a sequel and prequel to his first two feature-length films that would star John Travolta and Michael Madsen. Tarantino explained his idea on the Opie and Anthony radio show, "I even had a title for it. It was called Double V Vega. It would have taken place during the time Vincent Vega was in Amsterdam, when he was running one of Marcellus' clubs in Amsterdam. And Vic goes to visit him."
Who wouldn't love to see the hitmen Vega brothers together on the silver screen possibly discussing the merits of a Royale with Cheese? However, Tarantino admitted the time to make those movies has passed. "But we’re a little older now, and since they both [passed] — it would have to be a prequel,” said Tarantino. “I actually came up with a way I could have done it, even being older and [passed] where they all had older brothers and both of their brothers got together because the two guys [are no longer alive]. And they wanted revenge or something like that. But now, [the actors] are too old for that.”
The family-friendly movie Spy Kids is in the same universe as the gory Grindhouse movie Machete. How are the two connected? They are both directed by Robert Rodriguez, who vowed to put Danny Trejo in one of his very own films every year in order to turn him into the "Mexican Jean-Claude Van Damme."
Rodriguez was not able to cast Trejo in that many movies. However, the director did cast the actor in a few good films. Trejo only had a bit part in Spy Kids and its two sequels, playing an uncle to the Cortez kids and estranged brother to their father Gregorio (Antonio Banderas). His character's name in Spy Kids is, of course, Machete. The character finally got his very own film in 2010, Machete, a bloody revenge film that is absolutely nothing like Spy Kids.
Machete became such a cult hit that Rodriguez followed it up with the 2013 sequel Machete Kills. And just in case the world needed a little more Machete, a third installment called, Machete Kills in Space, is in pre-production at the time of this writing.