Stranger Things Theory: Who Gets Possessed By The New Upside Down Monster In Season 3

Will Billy and the Mind Flayer in Stranger Things Season 3

A new monster from the Upside Down is ready to take over the sleepy town of Hawkins, Indiana in Stranger Things season 3. Things aren't looking too good for Eleven, Mike, Will, Hopper, Joyce, and the rest of the Hawkins gang in a new Stranger Things season 3 trailer as the monster makes its presence known and announces its ready to destroy everything these characters hold dear.

One of the most curious parts of the final trailer is the voiceover prominently featured throughout. At the beginning of the trailer, the monster can be heard saying, "You let us in. And now, you are going to have to let us stay." It's a rather ominous proclamation, teasing the forthcoming battle the Hawkins crew are going to have to wage against the monstrous Upside Down ringleader and all of the other monsters it plans to unleash upon the town, as well as the rest of the world. But who exactly is speaking? The voiceover implies the monster has created a human host to work through but the host's identity is never revealed.

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It seems like Eleven will be responsible for fighting them and helping the host get freed of this new monster's grip, but who exactly will she be taking on? Ahead of Stranger Things season 3, here's who we think could get possessed by the new Upside Down monster.

Theory #1: Billy Gets Possessed By the Upside Down Monster in Stranger Things Season 3

Some clever editing in the Stranger Things season 3 trailer implies it is Billy Hargrove (Dacre Montgomery) who is possessed by the new Upside Down monster and whose body is acting a the host for the monster to work through. The voice certainly sounds like Billy's, a voice most recently heard in a new season 3 clip showcasing Billy as the new lifeguard at the Hawkins community pool.

Past season 3 trailers have also shown Billy isolated from the rest of the characters and having a much more troubling summer than them, too. Montgomery has been shown in the shower with a cut or growing wound on his arm, as if he's infected with something. The new trailer also includes a shot showing a bevy of rats scurrying into the Erimborn Steelworks, which matches an image of Billy standing outside the same building featured on a Stranger Things season 3 poster, implying this is the spot the new monster will be stationed at to work on achieving its goals on the Upside Down infiltrating Hawkins.

It's still unclear how Billy comes in contact with the Upside Down but all signs point to the encounter leaving a lasting (and potentially fatal) impression on Hawkins' newest resident. Could the marks on Billy's arm just be the first sign of a full-blown possession? Or will the new Upside Down monster use Billy in a different way to achieves its goals of taking over the town?

Theory #2: Will Gets Possessed Again in Stranger Things Season 3

Of course, it's also very possible Will Byers (Noah Schnapp) hasn't shook the hold the Upside Down had on him in Stranger Things season 2. Last season, Will was possessed by a smoke monster from the Upside Down. During his possession, his voice deepened and he became noticeably more menacing and powerful thanks to the monster's own power. This led to a jarring scene that could have been ripped from The Exorcist, with Joyce and Jonathan strapping Will to a chair in the shed behind their house and attempting to rid Will of the monster.

The latest Stranger Things season 3 trailer hints Will is still feeling the effects of his possession. At one point, he is seen touching the back of his neck in a movie theater. At another point, he asks Eleven, "What if he never left? What if we locked him out here with us?" Will is currently one of the few people who has had intense and prolonged experience with the creatures of the Upside Down, making him especially susceptible to another possession. Could the voice heard in this latest trailer be his, with the new Upside Down monster once again making his voice a little deeper and more menacing?

Theory #3: An Unexpected Character Gets Possessed in Stranger Things Season 3

There's always the chance the Stranger Things season 3 trailer is using some misleading editing to make fans believe either Billy or Will is the one speaking in the voiceover when really it's a character that hasn't been considered. The voiceover sounds like a young male, so if it's not Billy or Will, it could be Mike (Finn Wolfhard), Jonathan (Charlie Heaton), or Steve (Joe Keery). Puberty or not, Dustin (Gaten Matarazzo) and Lucas (Caleb McLaughlin) still have pretty distinct voices which don't seem to match what is being heard in the trailer.

Because Eleven didn't quite close the Upside Down in a way that kept it out of Hawkins at the end of Stranger Things season 2, allowing the dark alternate dimension to force its way into Hawkins in season 3, the chances for every character to have an interaction with the actual environment or the monsters who originate from there will increase. There will be multiple opportunities for Mike, Jonathan, or Steve to come in contact with one or more of the new Upside Down monsters and it's entirely possible those monsters will deem one of these characters the perfect host body to use as a means to achieving its plans for world domination.

Next: Stranger Things 2 Fixes Season 1's Biggest Problem

Stranger Things season 3 releases to Netflix on July 4.

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