Netflix's Stranger Things took the world by storm in the second half of 2016. The first season was wildly successful, quickly becoming a favorite of viewers and garnering critical acclaim. The show found the perfect blend of science-fiction, horror, mystery and adventure, appealing to a wide variety of audiences. All of this was wrapped up in just the right amount of '80s nostalgia to win the hearts of viewers without feeling like it was too much. People everywhere fell in love with the seemingly supernatural Eleven and the town of Hawkins and its inhabitants. The show's extreme popularity led to the internet overflowing with theories and discussions, including the classic #JusticeForBarb, for the fallen fan favorite.

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It was this level of popularity that brought huge levels of anticipation for season 2, and when Netflix dropped a teaser during the Super Bowl, the internet exploded once again. Barely any details had been revealed about the new season, but that didn't stop fans from trying to predict everything they could. As production continued, more news was slowly released about season 2, and the recent trailer from San Diego Comic Con added even more fuel to the fire. Excitement levels are high for the October release, but there are still lots of unknowns. Here are 7 things we know for sure about Stranger Things season 2, and 8 rumors we want to come true.

WARNING: Spoilers for Stranger Things seasons 1 and (possibly) 2.

15 KNOW: ELEVEN IS BACK

Eleven was the powerful child that stole everyone’s hearts in the first season. After escaping a government facility and meeting Will’s friends, she became a key to discovering the mystery surrounding his disappearance due to her telekinetic powers. Played expertly by Millie Bobby Brown, viewers were left devastated when she sacrificed herself to defeat the Demogorgon and save her friends.

Apparently, that is no longer the case as Brown has been cast in the second season to reprise her role as Eleven. It has also been confirmed by showrunners Matt and Ross Duffer that she won’t just be there for flashbacks, but that Eleven will be back from her supposed death. We don’t yet know how she will be back, but Eleven will be there for the ride.

14 RUMOR: ELEVEN IS THE DEMOGORGON

Perhaps the biggest rumor circling season 2 is Eleven’s true identity. A popular fan theory started during season 1, when Eleven tried to warn the boys that she was the monster. While on the surface it appeared as if she was saying that she was dangerous because of her powers, the theory goes that she was actually trying to say that she is the Demogorgon.

This theory grew in popularity and based on a few statements made by actors and the Duffer Brothers, it has picked up steam and has become a real possibility for the upcoming season. Based off of evidence gathered from season 1 and a few teases at Eleven’s role in the next season, it has become common for fans to assume that El and the Demogorgon are truly one and the same, or at very least share a similar origin.

13 KNOW: IT TAKES PLACE IN 1984

Stranger Things made full use of its 1980s setting, filling itself with pop culture references of the time and homages to classic '80s adventure, horror, and science fiction flicks. The first season was set in the fall and early winter of 1983, so the main cast of kids had the early '80s to play with when they would reference pop culture.

The new season will take place about a year later, around Halloween 1984. We have already seen the kids dressed up for Halloween as the Ghostbusters, so we know that the new season will embrace the setting and incorporate references to pop culture from 1984.This also means that enough time has passed between seasons to show us the repercussions on the town of Hawkins.

12 RUMOR: ELEVEN IS HOPPER'S DAUGHTER

Police Chief Hopper has a complicated, tragic and mostly unknown backstory, which has sparked up many a fan theory since season 1 was released. Very little is known about his past other than the basics. He fell in love and moved away with his wife; they had a daughter who died of cancer despite cutting-edge treatment, got divorced, and he returned to Hawkins.

After David Harbour stated that he has worked with the Duffer Brothers on exploring the character’s past and revealing that his daughter’s cancer is more important than people think, the rumors swirled. It is commonly believed that his daughter may actually have survived cancer but her mysterious treatments were government testing that left her with powers, meaning that she could very well be Eleven.

11 KNOW: SEASON 2 WILL BE DARKER

Netflix originally advertised Stranger Things as a nostalgia-induced horror/mystery, which it basically ended up becoming in terms of atmosphere and themes. While it did not turn out to be completely horrific, the show was pretty dark considering its main cast was mostly comprised of children and teens. Of course, elements of horror were present, but overall it as more of a science-fiction mystery/adventure with elements of horror sprinkled in.

Season 2 looks to be much more horror-influenced, as stated by the Duffer Brothers and many cast members, including David Harbour, who has been very active in discussing the new season. The discovery and infiltration of the Upside Down will have consequences on the real world, resulting in a season that will be overall darker and more focused on horror.

10 RUMOR: THE UPSIDE DOWN IS THE FUTURE

It appears based on posters and clips from the trailer that the Upside Down might be invading the real world in a bigger way this season. In fact, it looks like the world might even be turning into the Upside Down, meaning that reality as we know it will be destroyed and the Upside Down will be the only dimension.

This has led to the idea that in season 1, the Upside Down wasn’t another dimension, but rather a prediction of the future, where the world turns into it completely. Evidence has been brought up such as the Upside Down’s geography, which was exactly the same as the real world, from Will’s fort in the forest all the way to the inside of the Byers’ house.

9 KNOW: BARB WON'T BE BACK

Fan favorite character Barb was unfairly forgotten by the town of Hawkins after she disappeared just a few days after Will. Viewers were left with no answers as to her fate and she was barely even mentioned after she was taken to the post-apocalyptic Upside Down dimension.

It seems as though the internet and #JusticeForBarb are not going to get what they want, since she will be absent from season 2. It has been explicitly stated that Barb will not be back in the show, leaving fans to assume she is actually dead and will never get her justice. While it is sad to see that Barb won’t return, it has been hinted that her name will at least be mentioned in the season.

8 RUMOR: BARB WILL IMPACT THE SEASON

While fans may not be getting the justice they wanted for the relatively background character of Barb, it seems like she won’t be completely forgotten this time around. One of the biggest complaints about her treatment was the lack of attention she received after her disappearance, as the town never focused on finding her as much as they did poor ol' Will.

The Duffer Brothers have responded to these fan complaints, but have remained quite vague on the details, probably not wanting to spoil anything or get fan expectations up unnecessarily. They have stated that her disappearance (and most likely death) will be referenced in season 2 and will have some sort of impact on either Hawkins itself, or at least some of the characters.

7 KNOW: ICONIC '80s ACTORS IN NEW ROLES

Stranger Things has added new characters to the cast for the next season, and two actors who will be involved have been announced. Sean Astin will be playing Bob, the local RadioShack owner and high school friend of Joyce and Hopper. Paul Reiser will be playing Dr. Owens, a government agent tasked with covering up the events of the previous season.

Both of these actors were cast specifically for their iconic 1980s fame. Astin hit it big after being part of The Goonies and one of Reiser’s most memorable roles was in Aliens. Both are classic films of the 1980s that have helped inspire Stranger Things in one way or another, and it has been stated that Reiser was cast entirely because of his role in Aliens.

6 RUMOR: HOPPER IS WORKING WITH THE GOVERNMENT

Here’s an interesting one that’s actually two rumors in one. Hopper cut a deal with the government at the end of season 1 and was seen driving away in a government car. No one knows what went down in his time with the government, but it is known that in some way he had either joined them or is working with them in some kind of advisory capacity.

David Harbour has arguably been the most vocal about the upcoming season, and certain clues have been laid out leading fans to believe he will be secretly working with the government in season 2. One rumor states that he is now on the government’s side, while the other states that he is trying to take them down from the inside.

5 KNOW: WILL IS HAUNTED BY HIS DISAPPEARANCE

Season 1 ended on a relatively happy note as the Demogorgon was defeated and Will was saved and brought back home from the Upside Down. While the final moments of the season revealed a couple of loose ends to set up season 2, only one of these has been talked about in the lead-up to the season.

We still have very little information about Hopper leaving Eggo waffles in the forest, but we do know that Will regurgitating a slug from the Upside Down will have a huge effect on the character in season 2. It has been said by the Duffer Brothers that Will is not the same and is haunted and tortured by his experience being kidnapped by the Demogorgon. It is not known to what capacity it will affect him, but it is known that his experience has changed him.

4 RUMOR: WILL HAS POWERS NOW

While we do know that Will is strongly affected by the events of season 1, we still do not know to what capacity. Also, there is a chance that Eleven will not be in the season from the beginning, or even in the real world, meaning that there is a void to fill for a character with powers, or to join Eleven as either a friend or, as a swerve, as a fiendish foil.

This is where the idea that Will now has powers comes in. From the trailers, it looks like he is still very much connected to the Upside Down. Since there could be an empty space for a powered character, the rumor mill has pointed to Will taking that space due to his close ties to the Upside Down.

3 KNOW: THERE ARE NEW MONSTERS

The main monster seen in season 1 was the Demogorgon, and it had a huge impact on the show. This creature was the main link between the real world and the Upside Down and was also the first real taste of horror and supernatural creatures in the show.

Season 2 promises to introduce more monsters from different worlds, as evidenced by the poster, which showed us something horrific invading Hawkins. In the poster, a large creature with spider-like legs can be seen in the dark clouds descending on Hawkins. It is not known what this monster is, but we do know that we haven’t seen it before and it looks to be a big threat in season 2. Actor Gaten Matrazzo has also said that his character Dustin will bond with a creature from a different dimension.

2 RUMOR: THERE WILL BE MORE CHILDREN LIKE ELEVEN

Another rumor that provides a theory as to who is filling the void if Eleven is truly absent for a portion of the season is that we will be introduced to more children like her. Presumably, she is named Eleven for the fact that she was the eleventh test subject, meaning that there would be ten children who came before her, and possibly more after.

David Harbour’s comments about exploring more of the past of certain characters and aspects of the show has caused rumors to spread about season 2 revealing more of the truth behind the government experiments that took place in Hawkins, allowing room for more powered children like Eleven to join the show. Such exploration would open the show's mythos up even more, possibly making it an even more dynamic cross-genre venture.

1 RUMOR: THE NEW MONSTER IS MAN MADE

Season 1’s Demogorgon was named after a monster from Dungeons & Dragons, which the boys loved to play. In fact, its look was even styled after the creature from the game. This time around, the new monster promises to be even more menacing -- and certainly a lot larger -- but what it really is remains a mystery.

Based solely on its appearance, many fans have pointed out that it looks eerily similar to another Dungeons & Dragons creature: the Thessalhydra. While the Demogorgon was only based on its in-game appearance, the Thessalhydra is nearly identical, prompting the rumor that this time the monster was actually made by men who deliberately styled it after the game’s monster. Could that possibility open up even more questions as to the nature of Stranger Things' reality? Time will tell.

What are you looking forward to most in the upcoming second season of Stranger Things? Let us know in the comments!