If you're just biding your time until the Stranger Things 4: Volume 2 release on July 1, you will definitely want to read up on this pretty convincing fan theory that's floating around the Internet.
During the first seven episodes of season four, we're given some pivotal information regarding Eleven's connection to the Upside Down. As we explore El's past at Hawkin's Lab more deeply, we learn that she unwittingly assisted Dr. Brenner's first student, "Number One", in a plot to wipe out the facility and make an escape.
Volume Two is sure to provide more answers surrounding Vecna. Is he connected to the Mind Flayer? To demogorgans?
...Which brings us to one very mind-flaying theory about Vecna's role in the world of Hawkins. Could this creepy, crawly villain also have allies in the Right-Side Up?
Fans across the Internet say that Vecna might be working through Hawkins High counselor, Ms. Kelly.

Not only does Vecna have a thing for clocks, but we know that the grandfather clock in the Creel home has a keyhole which could, in theory, be compatible with Ms. Kelly's necklace!

On top of this, he also notes that a clock can be heard ticking in the background when Max visits Ms. Kelly at school and in her home.

Let's also not forget that Ms. Kelly did meet with a number of Vecna's victims. Yes, this could be due to Vecna going after kids with trauma, but it also could be how she feeds him information about their lives...
In the scene where Max goes to the counselor's office, Ms. Kelly blatantly asks about Max's sleeping troubles, one of the primary signs that Vecna is out to get you. A coincidence? Maybe...but consider me suspicious.
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Twitter users have also been pointing out other tie-ins to the Upside Down, like the clock in her office:
Ms. Kelly is up to some evil shit. The 7 is the 2 upside down. #StrangerThings
And how ~strange~ it is that two of her students wound up dead but she didn't come forward about anything:
keeping me up at night because how in the hell did Ms. Kelly have 3 students come to her within a week with the same symptoms and she didn’t report any of it to anyone. Especially when 2 of them end up dead. #StrangerThings
And that she could potentially be related to Vecna, or even have superpowers herself:
ms kelly HAS to be 1’s sister in stranger things season 4 😫