The following contains spoilers from Stranger Things Season 4, Volume 2, streaming now on Netflix.
In the first three seasons of Stranger Things, the last few minutes are very important. The series wraps up its world-bending drama with a few minutes of calm -- before something damning happens to keep fans excited about the next installment. In Season 1, Will was safe, but he coughed up a slug from the Upside Down. Season 2 ended with the Snowball Dance, but the Mind Flayer was lurking over the school. Finally, Season 3 showed "the American" in Russia.
All of those endings heavily hinted at what was coming in the following season. So, it's worth looking at the end of Season 4 to try and predict what's coming in Stranger Things' final season. Some things are obvious. Vecna will be back to exact his revenge on Eleven with more power than ever, and the city-sized fissure that led to the Upside Down is sure to be a problem. However, there was one subtle scene that gave fans a massive hint about what's coming -- and it involves Will Byers.
The scene in question happened right after Hopper and Eleven's meaningful reunion at the cabin. Everything is happy, but all of a sudden, something is very wrong. Will touches his neck; the Stranger Things main theme begins to play, and "snow" starts to fall. On the surface, the Upside Down was starting to assimilate with the Right Side Up, and that will be a focus of Season 5. However, it's interesting how Will touching his neck was the catalyst that shifted the scene's tone.
In previous seasons, Will touching his neck always implied that something bad was going to happen. Because he was possessed by the Mind Flayer in Season 2, he could feel the various evil creatures -- almost like his "spidey sense" for something Upside Down-related. At the tail-end of Season 4, he confirmed that he can still do that. Just before Hopper and Eleven's reunion, Will told Mike that he could remember what and how Vecna thought.
Quite a few fans took note of Will touching his neck in the super-sized finale, and a lot of them have hypothesized that Will's former connection to the Mind Flayer will be a big part of Season 5. One such theory was posted to Reddit by user u/StrangerWill. The theory predicts that Vecna wants to regain his human form, and he will use Will to do so in Season 5. Knowing that Vecna singled out Will in Season 1, it's a reasonable theory, but it might go too far. After all, Vecna already has a human form, and he has vowed to eliminate humanity.
Even if that specific theory isn't correct, the idea that "what began with Will, will end with Will" still holds a lot of weight. In an interview with Collider, the Duffer brothers teased that Will has a big part in Season 5. Ross Duffer said that Will's journey is "setting up us coming full circle back to Season 1. I think you'll see that with a couple of the character arcs, not just with Will. … The characters have maybe made steps, like in the case of Will, but that journey isn't over yet. All of that is going to play a huge role as we try to wrap this thing up next season."
From Ross Duffer's comments, it's clear that Season 5 will address Will and Vecna's connection. Vecna probably won't take Will's body as his own, but is likely that Vecna will try and utilize Will in some capacity. Maybe he'll try and make Will his lieutenant. Maybe Will has dormant powers. Maybe Will has to die before Vecna can be killed. The possibilities are endless, but regardless, it's clear that Will's connection with Vecna will be the focus of Season 5 when it kicks off at 100 mph.
To see more of Will and Vecna, watch Stranger Things on Netflix. Seasons 1-4 are streaming now.