Filmmakers James Wan and Leigh Whannell immigrated from Australia in the early 2000s and have since launched some of the most enduring horror franchises of the 21st Century. As writers, directors, producers, and even actors, the dynamic duo have blessed the masses with Saw, The Conjuring, and Insidious, the latter of which is about to drop its fourth Chapter; Insidious: The Last Key (directed by Adam Robitel) will hit US theaters on January 5th.

The Conjuring franchise especially has been flourishing in recent years; after stealing the show in the first film, released in 2013, Annabelle got her own franchise, and this year’s prequel, Annabelle: Creation, is a contender for best horror flick of the year. This ever-expanding universe will grow even larger when The Nun (featuring the demon Valak who terrorized The Warrens in The Conjuring 2) hits theaters on July 13th.

As The Conjuring, Saw, and Insidious franchises are all actively expanding, it’s worth wondering: Are all of Wan and Whannell’s films connected and, if so, are creepy dolls the key? Stick with us for a minute.

The latest trailer for Insidious: The Last Key (below) recently took the internet by storm, delivering high-impact jump-scares and a gloomy aesthetic that chills to the bone (not to mention the return of the shocking Lipstick Face Demon!). As we picked it apart for hidden reveals and Easter Eggs, we found a familiar face.

If you pause right around the 47-second mark, you’ll see an antique pinball machine; featured prominently is a ramp leading into the mouth of a ventriloquist’s dummy—the same dummy featured in 2007’s Dead Silence (screenshot above). Named Billy, he’s the preferred companion of Mary Shaw, the thespian-turned phantom who thrives on traumatizing children. While Dead Silence didn’t spawn any sequels, it nonetheless included a connection to another Wan/Whannell franchise: In Shaw’s workshop, we get a glimpse of another Billy: The tricycle-riding puppet who serves as a mascot and mouthpiece for John Kramer in the Saw franchise.

At this point, it’s not outside the realm of consideration to believe that Insidious occupies the same universe as Saw and Dead Silence, but how do these films connect to The Conjuring franchise? As previously mentioned, creepy dolls may be the key.

Wan and Whannell are clearly obsessed with dolls. We already mentioned Annabelle and the two Billy’s, but we also saw creepy dolls in the first Insidious (scattered about the Lipstick Face Demon’s lair). While evil dolls have been a common motif in horror movies since before Child’s Play, their prominence in so many of the team’s films can’t be ignored. When scrutinized, a connection can be made between Saw and The Conjuring.

Once again, near the beginning of Insidious, we see Josh (played by Patrick Wilson, who also stars in the first two The Conjuring films) sitting at a desk and on the blackboard behind him, we see an Easter Egg: It’s a doodle of Billy from the Saw franchise!

From here, it’s pure mathematics: If The Conjuring and Saw exist in the same universe, then Dead Silence is also part of that reality. And if the Easter Egg in the latest trailer for Insidious: The Last Key really is Mary Shaw’s Billy, then the Insidious films exist in that very same universe as well.

The Saw, Insidious, and Conjuring franchises span decades, but the prominent use of prequels means crossovers aren’t out of the question. Just imagine: Annabelle popping up in an Insidious film, or The Old Woman from Insidious haunting the Warrens in a future Conjuring installment. A prequel within a shared universe could also accomplish something the Saw franchise has yet to accomplish in earnest: Resurrect John Kramer. Though Saw doesn’t contain any of the supernatural trappings of the other films, I’d still jump at the chance to see Elise Rainier and her ghostbusters match wits with Jigsaw—perhaps by contacting the slasher’s victims in The Further! Hey Hollywood, give me a call!

Whether Insidious occupying the same universe as The Conjuring is an actuality or merely a fan theory, the reoccurrence of dolls in the films of James Wan and Leigh Whannell is still noteworthy. Clearly, they understand how the use of this motif taps into something primal, casting viewers into the deepest pits of The Uncanny Valley.

What do you think about the postulation that Insidious (and all of the horror films of Wan & Whannell) occupies the same universe as The Conjuring? Sound off in the comments section!