Zarah

If you claim that the duffers were in fact planning Byler romantically, and were aware of what was happening on set, but in your opinion backed out for some reason, then you can believe they are capable of leaving clever hints in their show, which means there is no reason to think they are not smart enough to leave hints that the show is not over yet.

If you think Byler was a plan, but Leight's plan, who wrote the series herself, then you really think everyone on set was too stupid to notice for 10 years that Ross's wife was being abused without giving her credit, or everyone on set is angry and ignored for 10 years that Ross was abusing his wife without giving her credit.

Or if you think the Duffers backed off from making Byler canon from spite on Leigh then you besicly saying Ross destroyed his and his brother's life work because of divorce and Matt just let him because yk bros before hoes

(I love your theories btw)

Heyyyyy :D thanks for the ask! Here's what I think:

Vecna is keeping Mike trapped via his trauma, guilt and insecurities. He is doing this by basically erasing and rewriting Mike's memories, in order to emphasise the stuff that will keep him trapped in negativity, and making him "forget" the stuff that would free him from that negative cycle. Love and memories.

I don't know how far back it goes, but in my opinion, ALL of Season 5 has been erased and rewritten... up until the Epilogue from Episode 8, The Rightside Up.

By that point, Vecna has kidnapped Mike and trapped him completely in an illusion world. The Epilogue is the moment that Mike goes from simply having altered memories, to entering the Rightside Up – a completely false reality that never happened.

So, what will free Mike?

Well, when characters have won against Vecna/the Mindflayer before, they did it through love and memories.

I went into this in my MWTFDYD = conformitygate analysis!

Max escaped with help from memories of Lucas and El. Will fought his possession with help from memories of Mike, Joyce and Jon. El rescued Billy with his memory of his mother. El saved Max with their shared memories, reversing her death. Love and memories are the key. If Mike was to remember his love for Will, he'd be able to escape – but that would ruin Vecna's plans. ...Which is exactly why conformitygate and MWTFDYDgate are intrinsically linked. The only way Mike can escape Vecna's curse is to REMEMBER what really happened in the months before the battle.

Not just before the battle, either. It may very well be that other seasons have been altered in smaller ways than Season 5 – but that's a theory for another day.

So, I think that Mike will need to do the same thing as the others.

He will use love and memories to save himself from Vecna – along with Will too, of course, who is not only the person Mike loves, but whom I believe is the illusionist powering the Rightside Up.

Vecna: We are going to do such beautiful things together, William. Such beautiful things.

Class: Magic-User (Illusionist)

Others have used love and memories to save themselves in the past - only, this will be the most climactic and meaningful example so far, because it involves A) Memories of scenes we thought we had already seen, and B) Mike's hidden love for Will. It'd be a big plot twist that would absolutely floor the majority of the audience! Including me.

Based on the reversed episode descriptions, I think that Vecna will allow El to "rescue" Will from his trance. However, like in Season 2, Vecna will use Will's powers in the background to keep building Mike's illusion, while simultaneously tricking Will's family and friends into believing nothing's wrong, and he's not possessed.

Additionally, Max will probably help Mike escape!

The reversed episode descriptions and some hints from my rewatches seem to suggest she hasn't woken up yet, and she'll be needed for the final battle with Vecna. Therefore: Max will use her knowledge of Vecna's mind to escape with Mike, like she escaped with Holly in the fake story.

Mike will most likely do it in a similar way to Holly; go through memory after memory, getting more intense, traumatic, and deeply buried as he goes on, until he reaches the moment that Vecna got him.

This twist will give the audience an opportunity to rewatch the show again and again (like how Mike will have to rewatch his own memories to discover the truth!)... and probably on a level that hasn't ever really been done before. If this theory's true, that is.

And, given the themes of love and memories? I think it will probably get insane and traumatic, but there will be a somewhat happy ending :P

I've been thinking about this post for a long time, and all the connections which I'm going to try to point out, because the maps are so frustrating, but so interesting.

(thank you also to Naomi, Goat, Ace and others in the discord for letting me yap about if any of this might actually make sense!)

Firstly, let's start with the wormhole that might not be actually a wormhole, but still "only" a Wall, circle (a wheel) in the Upside Down

“While the existence of wormholes is entirely theoretical, they have captured the fascination of scientists and science fiction writers alike. (...) If wormholes did exist, they would be extraordinarily unstable. Their enormous gravitational force would rip them apart at the very moment they formed.” - Mr. Clarke, 5x3

let's go with Dustin's first idea what the wall around UD is a circle, a wall all around:

(remember the algebra, it will be another point later on.)

"So the lab created the wall?" - "No idea. But i think we should find out."

map no. 1: Dustin figured out with 3 points what proportion the circle around Hawkins would be. What's interesting is (and this I've seen in this amazing post by @zephyrcryptid) that the Lovers Lake is within the circle on this particular map! (Either it's a incorrectly printed version with the Lake pasted onto the wrong square, or... and this is the part I want to maybe focus more in this post - the lake is moving locations.

(I know, I know, that's "impossible", "that's just prop error", "it doesn't mean anything". Well, humor me. Why not. It's impossible? Maybe, maybe more improbable, but nothing is impossible, especially in a scifi tv show where they talk about wormholes existing, right?)

It's only later when Dustin finds Brenner's notes on what the Wall could actually be, he thinks it's a wormhole, (same as in 5x3 we as audience think to connect Mr. Clarke's class and Erica saying what wormhole is, it lead us to think it's the case of the actual wormhole, because we see it on the board).

then it's even more enforced with what the characters later discuss in 5x7, and what the Duffers showed us in the 'documentary' - but none of that necessary have to be the truth - as this show likes to play with the perception of what is or isn't reality, also because of the reasoning that a wormhole would instantly collapsed after forming, and because of the exotic matter - which still remains a big unknown in how it relates to the UD.

but what's more important and what I want to focus on here - is how this scene above with Dustin, is followed by Max searching Henry's memories and throught those she hoped to find the exit:

She found the memory of Vecna first targetting her, beyond the Rainbow room - which is in the Lab, and, as we know, the Lab is the center of the Wall). so the memory is literally hidden behind a wall, a wall Max even had to tear through to get to it.

and what's more - it showed us Mike first, sitting beside Max during a math class,

And before you say that I’m out of my gd mind, check this 👇

1. The unicorn

So I’ve been examining El’s things looking for cg details, and one of the first thing I see is a horse? Even a unicorn, which is horsegate, right? (Next to it there’s El’s dictionary, which is fair, and also some cassettes that mb should be studied more.)

But what can it symbolise you might wanna ask! And I want to thank you for this question because this unicorn is literally the first and big detail that we see right away, having such a meaning:

(Which emphasises that in the 80s it would definitely make sense to have it in the shot as a symbol.) Okay, cool 🥲 Let’s move on.

2. Mike’s photo from Halloween

having no connection to El whatsoever, but guess to whom Halloween might have a connection (something something crazy together). Why would El have exactly this photo on her table? Is it the only photo Mike has which he could give her? But guess who would have it logically if they dated ever since? Hmm.

3. The silver cat! Not sure if it feeds but it’s definitely there. The silver cat that feeds when blue meets yellow in the west. If it is originally a byler scene, would it mean the blue met yellow, and having a silver cat then would make sense? And guess what else is there: 1) another horse? 2) a heart with a rainbow 3) DRAWINGS

(Also a small details is that two last names on the shot are Russian, and even Michael Park could be Russian. Not sure if it’s important, but take it anyway as a 3s Russian-plot detail)

4. Now the most intriguing part

Firstly I noticed a mask that El probably took from Kali, which is an interesting detail itself, however what is even more interesting is semi-transparent editing of THE DRAWING OF PALADIN. We never focus on that, it’s never actually in the shot, but it is. It is hanging on the wall but it was shot playing with our attention. (Check the left side of the shots.)

Now tell me pls. Why THE FUCK would Mike gift her a drawing of Paladin? Or do you want to tell me that El is a person who actually draws? And she drew Paladin and left it on her wall? That she knows who that is?

Guys, honestly, unfortunately, I don’t know shit about D&D world, and only the sword gave it to me in this shot. But do you actually want to tell me that there’s another explanation why this drawing even exists in that room?!

4. The picture from Mike’s basement.

Could be a nice detail for milkvans, like, oh, look, he gave it to her!

But… do you really think Mike’s parents would give away a giant picture to… where exactly? To the girl about whom they don’t even know? That Mike would take it out of his basement? The most weird gift for 14 year olds. If Mike really wanted to do something nice to or for El, he could do anything but this, to be honest. It just doesn’t make sense. And I’ll tell you in the end of the post what does…

5. THE CLOTHES COLOURS 💛💙

Mind you, it is the same season where Mike and Will are associated with blue and yellow strongly! And watching this scene today, I got puzzled again, like, why El is even in that blue t-shirt?

And pay attention to the green wall of the room:)

When I rewatched this scene now a couple of times, trying to see every detail and REALISED THAT PALADIN WAS FUCKING THERE I had such a revelation OMG.

It’s not El. Never was!!!

And the blue t-shirt is Will’s t-shirt!!

Now, drawings on the table are of course Will’s drawings. The silver cat, the yellow and blue t-shirts, the fucking GREEN wall — all of it symbolising byler! And that damn picture hanging, again, initially in the basement… All the drawings on the wall — what does it remind you of??? Maybe Will’s drawings in the basement?

Doesn’t it give Will and Mike kissing there, Mike having Will’s drawing of him as Paladin, and the heart with a rainbow, like the one being there since season 1, is still there and never was taken out like the big picture never did?

I mean, technically, it’s another heart pic, but the concept is the same, and why wouldn’t it be corrupted this way too?

now if you have a question how’s it possible: my nowadays theory is that ST got corrupted between s2 and s3 (same place where Tales will take part), changed the vibe in s3 and ever since have been getting flayed more and more; s2 ends with the Snowball leading to Hawkins being turned upside down, and the only thing that it was associated before was that the UD is still there, which was not the news. However, for some reason they showed us that turning. For showing evil they didn’t need to turn anything in the end of s1. And, as a hint, in 3x01 we even have Will’s clothing matching s5 dial’s arrow.

So, I believe, all these details from 3x01 tell that it was a basement byler kiss in the basement. Looks like it indeed was a double date with lumax in the cinema. And probably even Snowball happened the other way.

That would also explain side-lining Will in season 3 because he was lwk performed by El that season…

Short answer: Probably :P

No intro, just look at this. Here is a list, step-by-step, of what Will and Mike BOTH did, in two totally separate scenes from each other.

Both Will and Mike…

Visited the hospital.

Left the room they were in.

Bought a caffeinated beverage from a machine.

Bought one for another person (or tried to, but were declined).

Started walking back.

Stopped when they saw something through a gap.

Reacted in an extreme way.

Never finished their own caffeinated beverage.

May I repeat again: All eight of these actions occured In two completely separate scenes from each other, in the EXACT same order. If that is a coincidence... well, then I'm gonna buy a lottery ticket tomorrow and hope I "coincidentally" get all six numbers correct and in the exact same order.

Based on these eight consecutive parallels, the only conclusion I can come to is that both Mike and Will were in the same scene.

(...given my pre-existing theory that every scene in Season 5 was an illusion based on real events, of course.)

My rightsideupgate posts for context! (just read part 1 if you're new) ORDER OF EVENTS: Part 1 (Reality = reversed), Part 3 (12 Episodes), Part 4 (MWTFDYD), Part 9 (Wheeler attack -> Mike's kidnapping), Part 11 (Mr Whatsit = Will) SCENE ANALYSIS: Part 2 (Will/Robin), Part 5 (Rainbows), Part 6 (The roof talk), Part 7 ("Where's Dustin right now?"), Part 8 (El is missing), Part 10 (Byler's missed date), Part 12 (Byler saw Rovickie kiss), Part 13 (Will's painting)

So, which scene is real? Mike's or Will's?

You tell me.

OPTION A: MIKE'S SCENE

Will and Mike both leave the hospital waiting room to get caffeinated drinks.

They go down the hallway and stop when they see A Wrinkle In Time through the window.

They both look at it.

Will is so shocked by seeing A Wrinkle In Time that he drops his drink and frantically runs away, while Mike just stands there, totally quiet, overwhelmed by thought.

OPTION B: WILL'S SCENE

Will and Mike both leave Max's hospital room to get caffeinated drinks.

They go down the hallway and stop when they hear something through the door – Robin's voice, and an unfamiliar one.

They both peer through the gap and see Robin and Vickie kissing.

Will is so shocked by seeing two fellow queer people kissing that he drops his drink and frantically runs away, while Mike just stands there, totally quiet, overwhelmed by thought.

Ah yes, A Wrinkle In Time, of course. The most shocking book known to humanity, right?

...Obviously Option B (the kiss) is the most sensible option here. Both Mike and Will's reactions make sense. Plus, it's more suspenseful, dramatic and interesting for ALL FOUR of these characters!

Additionally...

Mike was mentioned in the scene before Will’s, and Will was mentioned in the scene before Mike’s.

Lucas was in both Mike's and Will's previous scenes!

The puzzle in Mike’s scene has prominent rainbow imagery, a symbol frequently associated with forgotten memories in this show – also, classic queercoding! Especially considering the context that Mike may be misremembering a queer kiss.

Will’s scene has no rainbow imagery, further suggesting that Mike is the one misremembering most of the scene, and less so for Will.

Taking the theory further

Now, our current interpretation of the scene is fine as it is. It's very plausible, and we don't need to change anything else for it to make sense. We can totally just leave it there.

But... I have a sneaking suspicion that Mike was the one who ran away, not Will. Just look at this.

Evidence for Will running away:

On Halloween, he ran for shelter after being bullied + seeing visions of the Upside Down – ST2

Will biked away from Mike and Lucas after they weren't being respectful about his D&D campaign – ST3

As you can see from the evidence above, it wouldn't be totally strange for Will to run away from something! It's not impossible.

But this is not how Will usually deals with things. Will as a character is not known for big emotional freak-outs. He usually freezes, goes quiet and keeps it all inside. He usually does not express his emotions in any way except through art. When he cries, he often tries to hide it.

But Mike, on the other hand?

Evidence for Mike running away:

There have been many occasions where Mike's emotions physically exploded out of him on impulse, especially when he was a child with less self-control.

Destroying Eleven’s blanket fort – ST1

Pushing Troy to the floor – ST1

Yelling at Max and throwing a broom to the ground – ST2

Punching and yelling at Hopper – ST2

Giving up and walking away from Will during the Rink-O-Mania fight – ST4

Impulsively trying to get a hot orange mohawk – pre-ST5

Mike often tries to escape his problems, pretending they don't exist; he would rather just pretend everything's fine, and nothing is wrong. 

Hiding away to make out with El instead of hanging with the Party – ST3

Not sending Will any letters – pre-ST4

Telling El he’s gonna “fix this” after she was arrested – ST4

His "could that be real for us?" conversations with El; he later said that it was a “fantasy” plan, and he should’ve had something more “real” – ST5

Choosing to believe in a fantasy story where El escaped, after she died – ST5

Damn, it's mostly w/ El. I swear it wasn't on purpose lol

Mike is way more likely than Will to A) literally run away from his problems, and B) have a big, physical reaction to said problems.

Therefore, I think it was Mike who ran away.

So What Happened?

Well, after Robin and Vickie saw Mike run down the hallway, the scene cut off.

Vickie: Who is that? Robin: Shit. (this parallels the pipe scene, when Ashley Klein runs away after catching Mike and Will... Mike: Shit.)

That's the exact moment that Robin and Vickie would've come face to face with Will, still frozen in place, completely quiet, keeping all his emotions on the inside as usual...

Mike may have dropped his drink, leaking it everywhere. Like the pipe scene, in which MIKE'S shovel breaks the pipe and causes a leak, splashing on both himself and Will.

Since Will was the one still standing in the hospital hallway, Robin would have talked to him first.

^ This re-contextualises Robin's hospital scenes with Will! Instead of returning there on some random mission, Robin and Will never actually left the hospital. They had their talks that same day.

As for Vickie – she's literally at work, so she trusted Robin to talk with Will for now.

After that, Will may have gone back to Max's room with Lucas, who again, was in both Mike and Will's previous scenes.

HOLY SHIT!!!!!! OH MY GOD!!!!!!!!! Sorry, I got excited.

You know how during their hospital chats, Will asks Robin about the signs that someone wanted to date, and after she told him several things that he and Mike had already done before, he WENT QUIET AND STARTED SPACING OUT WITH HIS EYES DARTING BACK AND FORTH IN REALISATION????????

Will in the hospital after a revelation, spacing out, eyes darting back and forth in realisation...

Well, there's another scene in the hospital in which a character totally spaces out with his eyes darting back and forth... Mike! AFTER SEEING A WRINKLE IN TIME + THE RAINBOW PUZZLE!

Mike in the hospital after a revelation, spacing out, eyes darting back and forth in realisation...

Taking everything else into account, this is a big clue that he may have actually been Will.

Will sits back down after his talk with Robin. Lucas: They still won't give us a timeline on Max. [...] Lucas: Will. Will, are you listening? Will snaps himself out of it.  Will: Yeah! Yeah, no, uh... I was thinking about something Robin said earlier.

The next day, Robin would've had this conversation with Mike. I highlighted the important parts.

Robin: Were you at the hospital yesterday? Mike: THE HOSPITAL? No! No. No, no, no. Robin: Weird, I... Mike trips over in a panic. Robin: ...could've sworn I saw you there, but um... Vickie, she's a candy striper. Mike: Oh, yeah? Robin: She's my friend. We're friends... good friends. But uh, the thing is, some people might not understand our friendship. Mike's eyebrows furrow. Robin: Basically, what I'm trying to say is that if you were there and you did see something, it might just be better if, uh, nobody knew. If it stayed between us. Mike: I didn't... see anything.

First of all, the "No, no, no." Mike always repeats himself.

Second of all, insisting he wasn't there and didn't see anything? Classic Mike, denying all his problems and pretending they don't exist.

Third of all, this is an excellent parallel to what Mike said to Will the previous season.

Mike (ST4): Friends... best friends. Robin (ST5): Friends... good friends.

Because if Robin talks about her girlfriend the same way Mike talks about his best friend... well. It would totally re-contextualise Mike's words, and give him a lot to think about, wouldn't it?

Finally, this would explain why Robin and Mike seemed closer in the latter half of Season 5, when we never saw them hang out at all!

Why It Makes Sense

Why would Vecna invent an imaginary scene in which Robin and Vickie kissed, then got caught? He wouldn’t. It really happened.

Why would Vecna remove Robin and Vickie kissing if it’s a catalyst for Will’s queer self-acceptance arc? He wouldn’t. Will's queer self-acceptance arc helps him to discover his powers, AND helps him to "get over" Mike... at least, in Vecna's telling of the story. So Vecna couldn't remove it.

But if catching Robin and Vickie kissing was a big catalyst for MIKE'S queer self-acceptance arc? Oh. Now that would be a problem. To keep Mike trapped in his illusion (the Rightside Up) Vecna cannot let Mike feel secure about who he is. He needs to keep Mike trapped via guilt, trauma, insecurity and self-loathing.

Ergo; though he may not be able to remove the scene altogether, Vecna would absolutely have reasons to remove Mike from that scene!

Especially if it meant that Vecna could repurpose that scene to A) give Robin + Vickie relationship issues (as I explored in this analysis), B) force Mike to never have the self-acceptance arc he desperately needed, and C) force Will to "get over" his feelings for Mike and settle for a lookalike.

Three birds with one stone.

A Fantastic Opportunity

This would also be a fantastic opportunity for characterisation and plot development!

It’s an interesting glimpse into the way both Mike and Will deal with their emotions; one reacts very physically and impulsively, while the other freezes in place and only reacts internally. 

It’s a great way to expand on the pre-existing foundations of Will’s queer self-acceptance arc as well as Mike's... AND delving deeper into Robin and Vickie's experiences!

Vickie could be given some character development! Not only would she be interacting and bonding with the main characters of the show for the first time, she would be dealing with a very confronting situation – also in a different way from Robin. 

Vickie used to have a boyfriend she was very openly dating, so having a secret relationship is probably a new experience for her – and a scary one, given it might also be her first queer relationship. This variety of experiences would make the show interesting for the audience, and maybe give them something they haven't seen on TV before (which the Duffers have said they wanted to do).

Vickie: Okay. [...] Bottling… bottling emotions.

So many possibilities!

Furthermore, if Mike found out as well as Will, and Robin bonded with him (mentoring two characters, not one, like Maya Hawke said), then that means we will unlock a whole new set of conversations and interactions between these two characters, and therefore even more of a glimpse into Robin’s and Mike’s emotions! This would create a more interesting story, so the new episodes wouldn't just be repeats of the old ones.

Again, as I stated previously, this would explain the scenes in Vol. 2 where Robin and Mike are bickering as though they're friends.

But Vecna removed Mike's self-acceptance arc. Because of that, he doesn't have to deal with Mike and Will's love saving either of them from his curse. All he had to do was remove Mike from scenes like this one.

(That's what he thought, anyway.)

(But Will's painting is still hanging on Mike's wall...)

...

Thanks for reading!!!

"Jonathan STOP IT now"

"no no Will– it's okay"

Or rather, why Vecna chose to appear to Holly as "a friend" in Season 5...

...and why this has been foreshadowed from the start.

Theory Overview

Theory Summary

1) Mr. Whatsit is in fact "real"

2) Evidence Vecna disguised himself as Will to Holly

3) But how???

4) The Party found out... but they couldn't save Holly

5) What does Vecna want with Holly and Will? Season 1-2 told us already...

Final summary

Theory Summary

After "stalking" Holly, Vecna disguised himself as Will (someone “gentle and kind”, a "friend”) in order to gain her trust.

Will: “I was him. I was Vecna.”

Mr. Whatsit, AKA "Will", told Holly that “there are monsters in Hawkins”, that they eat kids like her... and that he was attacked by a monster when he was a kid!

Mike and Nancy realised that Holly was a target, and told her that Mr. Whatsit was the monster, thinking they could stop his plan.

But then, on November 3rd, Vecna sent a Demogorgon to attack the Wheelers. Mike and Karen were heavily injured in the attack… but Mr. Whatsit “saved” Holly.

Mr. Whatsit: The monsters, they tried to take you. But I saved you just in time.

He took her to the Wheelers' front door – the Demogorgon’s gate to the Upside Down. He told her it was their exit. A dimension door.

Holly: It doesn’t look like an exit… are you sure you’re not a monster? Mr. Whatsit: Pretty sure. 

He convinced her that he was a hero, not a monster.

And so, when Vecna took Holly into the Upside Down, there wasn’t a struggle – he proved to her that he wasn’t a monster through a staged rescue, which was really a kidnapping in disguise. 

This explains...

Why the concept of "Mr. Whatsit" was introduced at all

Why Mr. Whatsit's identity was framed like a huge reveal (it is!)

Why the characters never realised who he was until Holly was already taken (they did realise – they tried to save Holly, not Derek)

Why Holly wonders if Max is a monster, but it never amounts to anything (it was about Mr. Whatsit, not Max)

Why the "we have to save Derek" plotline was so important (it was Holly, who is much closer to the Party)

Why Will is repeatedly said to literally be Vecna

and more!

^ there's evidence for all of this!

Now let's get into that evidence!

First, as always, here's a brief overview of my main theory:

MIKE IN THE RIGHTSIDE UP

Mike is stuck in his own version of Camazotz: the Rightside Up.

In the 8 months after Season 4, the gang prepared for a big battle with Vecna. On November 3rd 1986, the Wheeler house was attacked and Holly was taken; then, on November 6th, Mike was taken – on the anniversary of Will's disappearance.

Every important plot point from Ep 1-8 was an edited version of what really happened in those 8 months. Vecna just changed the order, characters or context to suit his own narrative, keeping Mike trapped in the Rightside Up. That's why Mike's real memories will be crucial to his escape in the upcoming episodes: a reversal of the current episode descriptions.

Evidence! ORDER OF EVENTS: Part 1 (Reality = reversed), Part 3 (12 Episodes), Part 4 (MWTFDYD), Part 9 (Wheeler attack -> Mike's kidnapping), Part 11 (Mr Whatsit = Will) SCENE ANALYSIS: Part 2 (Will/Robin), Part 5 (Rainbows), Part 6 (The roof talk), Part 7 ("Where's Dustin right now?"), Part 8 (El is missing), Part 10 (Byler's missed date)

1) How do we know Mr. Whatsit is “real”?

First of all, how do we know that Mr. Whatsit even… well, exists in the real story?

As I said: every major plot point is based on something that really happened, and Vecna would have changed as little as possible to make it as believable as possible. So if there's a plot point which has huge ramifications and impacts multiple scenes, it's almost certainly part of the real story.

If Vecna didn't target Holly as Mr. Whatsit…

Three big scenes would not have happened (Mike telling Holly that she doesn’t need Mr Whatsit, “What if Mr. Whatsit is real?”, Mr. Whatsit's big identity reveal)

Will would not have realised the full extent of his powers by seeing through her eyes, and his entire character arc would be impacted

Three MORE big scenes would not have happened (Will’s self-acceptance moment + killing the Demogorgon(s), saving Max and Holly, falling into a trance)

Sounds like a pretty big deal to me!

Considering these ramifications? At the very least, Vecna targeted Holly in a way that allowed Will to see through her eyes – and most likely, he did it as Mr. Whatsit! 

We can pretty safely assume Mr. Whatsit exists in the real story.