The old grandfather clock in the Creel House is a significant image throughout the trailer. Viewers see it in the Creel House, in the Upside Down, and half-buried in a wall with Max staring at it. It could be the house’s entrance to the Upside Down, but it could also represent time travel.

Fans have been wondering if time travel would happen in Season 4 after Hooper’s final letter talked about “wanting to go back” and redo everything. But this theory is more based on the constant appearance of the clock and the Duffers’ emphasis on it in a new IGN interview that breaks down the trailer. “It’s a really core part of the mystery that our Hawkins group is trying to solve,” Ross said. “I don’t want to give away too much other than to say this clock plays a very, very important role moving forward.” They also mentioned Max should not have seen the clock. (Poor Max.)

Speaking of Max, some fans think Max has somehow gained Eleven’s powers — or worse, stolen them.

The inference is easy to see. In the trailer, Max is floating like she’s the one with psychic abilities instead of Eleven, juxtaposed with a clip of Eleven telling Dr. Owens she no longer has her powers. Did Max wish to be powered like Eleven is, to help protect Hawkins now that the Byers-Hopper clan has gone off to the West Coast? Did the Upside Down flip reality and grant her wish? Is that why she saw the clock?

One of the more exciting details in the trailer is the Stranger Things 4’s monster of the season. Season 1 had a Demogorgon, Season 2 had the Mind Flayer and Demodogs, and Season 3 had a different version of the Mind Flayer, when he took over Billy Hargrove’s body.

Season 4 now has its first humanoid-shaped monster, which the Duffer brothers revealed in their IGN interview is called “Venca.” Venca is a Dungeons & Dragons villain from the Forgotten Realms stories, described as “a once-human lich from Oerth who ascended to godhood.”

The question, of course, is: Who is Venca? There are many theories, but the most obvious is the Mind Flayer. Perhaps having tasted bipedal living, he’s created his own body, which looks like the D&D monster and is now roaming the earth.

If this season is all about Max trying to get Eleven’s powers to change the world somehow and bring Billy back, then fan theories logically deduce that Billy is Venca.

Rumors have been swirling on Reddit for months that Dacre Montgomery (who played Billy in Seasons 2 and 3) is back for Season 4. The Mind Flayer already took him over once; that makes him the easiest target to do it again.

The third and final camp believes that Robert Englund plays Venca, which can only mean one thing: This monster is none other than the character Englund plays, Victor Creel.

There’s a sound logic here. The trailer ends with a creepy voice that sounds suspiciously like Robert Englund’s Freddie Kruger and the appearance of a human character emerging from the Upside Down. The Creel family moved into the house back in the 1960s, and something inside it took out everyone but patriarch Victor. If it was the Upside Down that ended his family, perhaps it infected Creel as well.

This is one of those “blink and you’ll miss it” details from the trailer, but that’s what the hardcore fandom is for, to spot the things you miss. In this case, it’s Billy’s gravestone.

At the 32-second mark in the trailer, as Max starts telling Billy how terrible everything has been since he passed away, the camera puts his gravestone from and center. It reads: “Billy Hargrove: March 29, 1967 - July 4, 1985. Gone, But Not Forgotten.”

But at the 2:37 mark, as Max floats upwards to the shock of her friends, look again at the gravestone. It reads: “William Hargrove: March 29, 1967 - July 4, 1985. Gone, But Not Forgotten.”

Perhaps it’s the proliferation of multiverses in the current science fiction landscape, but some fans have convinced themselves this means there are parallel universes at play. Perhaps the Upside Down isn’t just a gateway that can travel long distances in a short amount of time, but also one that can let people pass between worlds.

With all the images of Eleven’s time with Dr. Brenner and the confirmation Matthew Modine will return in Season 4, some fans are convinced that Eleven and Max won’t be the only powered people in the season.

Eleven’s trip to Chicago didn’t go over well with some fans in Season 2, and that’s because the show took the audience someplace they’d never been, did nothing, and then sent everyone back on what felt like a useless field trip. Bringing the mountain to Hawkins, as it were, both gives the show a chance to redeem that storyline and put the characters in a place where they could actually do some good.

The final theory, and perhaps most sensible, isn’t about the details of this season, but rather how Stranger Things’ final two installments will play out. A theory going around Reddit posits that the Duffers plan to follow the same model Marvel followed to bring closure to the Infinity Saga.

That means Stranger Things 4 is the “darkest before the dawn” part of the story. In short, the kids will not win this time. For whatever reason — lack of teamwork, a problem too significant for teenagers to handle alone — Season 4 could end on a final tragic note. Stranger Things 5 would then be about picking themselves back up, coming together, and defeating the Upside Down.

Suppose that’s the case, fans better stock up on tissues. Stranger Things has never been this scary.