Part of the fun of shows like Stranger Things is trying to figure out just what twists the mystery might take. Season 1 ended with some threads neatly tied up and others unspooling, leaving fans to wonder if things were really as contented as they seemed to be. Some characters have vanished and others have returned, but it's likely nothing will be that simple when – and if – the show returns for Season 2. Stranger Things may have returned Will Byers to his home, but he's still haunted (or maybe more than haunted) by the things he experienced. And young heroine Eleven evaporated, but is she really gone? These Stranger Things Season 2 theories attempt to flesh out the questions that remain.
The guys behind Stranger Things, Matt and Ross Duffer, have discussed how they would want a second season to play out like a sequel to a movie. So even though certain plot elements came to satisfying conclusions, such as Will's return and the monster's defeat, there were still cliffhangers to spare. Will's back, but he's also coughing up leech-like creatures and flashing back to the Upside Down universe. And the monster may be gone, taking Eleven with it, but police chief Hopper is still leaving snacks out for her in the woods.
Eleven Is Dr. Brenner's Daughter
Despite the journey Eleven went on, both physically and emotionally, over the course of the series, she's one of the characters with the most theories attached to her. Fans still don't really know where she came from or where she ended up. One possible explanation of her origins is that she is the daughter of Dr. Brenner (who she referred to as "Papa") and his former patient Terry Ives, who alleged that her daughter was stolen by Hawkins Lab.
Eleven Is Alive
Hopper leaving some of Eleven's favorite food (waffles) in a mystery box in the woods is definitely an eyebrow raiser. Even though Eleven blinked out of existence to take out the monster, it's plausible that she's still out there somewhere – specifically, she might be in the Upside Down. Hopper could be leaving the food so that she doesn't go hungry; the Upside Down is a reflection of the regular world, and items like food may be able to cross over.
Eleven Comes From A Parallel Universe
Instead of having earthly origins, perhaps Eleven is actually from the Upside Down. Sure, she's a lot cuter than the monster but there is an obvious connection between the two. She referred to herself as "the monster" and she was the only one able to defeat the creature. Plus she has all those crazy powers. Perhaps Eleven isn't really from our world at all, and that's why her connection to the Upside Down runs so deep.
Hopper Has A Secret Agent Past
Hopper was clearly a very different guy before the series started. It's implied that he went off the deep end after the death of his daughter, and flashbacks certainly show a different man than the one we come to know over the course of Season 1. At the end of the finale, he climbs into a mysterious government car for reasons that remain unknown. One theory posits that he used to be a federal agent and is rejoining, supported by an offhand comment about him being a "big city cop" once upon a time.
Eleven Is One In A Long Line
The fact that Eleven is called by the number printed on her arm ("011") seems to imply that she is number eleven in an experiment that saw ten other test subjects before her. Reddit user xChri5x suggested that Eleven was actually the eleventh clone of Terry Ives' missing daughter, which would definitely be a shocker. There's no way she was the only experiment being run at Hawkins Lab.
The Upside Down Is The Future
There's one theory that the Upside Down isn't just a parallel universe: it's actually the future. It is the Hawkins viewers have come to know, just years after it became overrun with monsters thanks to Will coughing up one of the Upside Down's slugs into the sink. It's kind of a closed time loop deal, but it's possible. There is a lot fans don't know about that other world, and a lot of questions for the show to explore in Season 2.