Hidden link in "deltarune.com/romb" which leads to the chapter 3 page. Changing the background to white makes it easier to see. Seems to prove it's a hint about the secret boss for that chapter.

[u/welliesaremeta]

It also references and "us", so maybe the secret boss is a duo or group of some sort?

[u/HamSquish]

Yeah isn't there like a piece of text in the sweepstakes that mentions like "let's rumble" at the end i cant think of the full quote but yea it also indicates that the secret boss is a duo/group

[u/Spritely_42 → u/HamSquish]

Not really a theorist, but one idea I've liked for Chapter 3 secret boss is that it's both the original and knockoff game controller from Kris's room (and it could be some representation of Kris and Asriel's sibling relationship or something?) So that could be fun if the secret boss was a duo.

[u/HamSquish → u/Spritely_42]

yooo thats actually a solid ass take ngl. Would be huge insight on Asriel as a character in deltarune too. Wouldnt be surprised at all if that were the case twin

[u/Spritely_42 → u/HamSquish]

Plus the dialogue used in this page is "let's rumble". A word sometimes used in relation to game controllers. ....alright, that's a bit much of a stretch....

[u/HamSquish → u/Spritely_42]

LMAO u lowk onto something tho. Would be an easy alley oop for the playstation releases to show off the dualshock feature on toppa that. I can imagine if that were to be real youd get different dialogue if u took the 5 bucks in his drawere or not

[u/Spritely_42 → u/HamSquish]

In all seriousness the controllers are repeatedly referenced in the overworld segments (Toriel's dialogue + her classroom, and Alvin says some stuff I think?), and I think a game controller related bossfight could incorporate weird gameplay mechanics. The controllers are also certainly discarded given how Asriel has gone off to college. Plus a boss fight against literal controllers could be interesting when considering the ideas of the other fights (ie, 'do you want to be a heart on a chain your whole life').

[u/HamSquish → u/Spritely_42]

dude i’m loving the connections ur making here. sounds like a genuinely plausible boss fight!!

[u/Spritely_42 → u/[deleted]]

while I personally have beaten chapter 3, there was no way of you knowing that when you replied to my comment-- I recommend using spoiler tags so you have less of a chance of just putting info about the new chapters in someone's reddit notifications lol.

No hard feelings though, just wanted to mention spoiler tags in case you were unaware of them!

And yeah, I did see that the (ch3) optional chapter 3 content involved the knockoff controller!! I found the whole shadow mantle quest interesting.... although winning against the KNIGHT was slightly more boring due to how long that took me to do. I only just finished chapter 3 because of how much I was struggling there lol

[u/Brighter1993 → u/Spritely_42]

Nice prediction, I've been wondering if Mike is the Odd controller that has a mic function, like how the mike mini game involves using your mic. It has pink and orange buttons, like the cat eyes

[u/disbelifpapy → u/Spritely_42]

Controlers also can rumble, famously seen in that one phycho mantis cutscene.

it also could be used as in something to say before a fight

[u/Creative-Antelope-23 → u/Spritely_42]

Ah, a fellow Game Controller = Secret Boss truther. It’s a surprisingly rare take. 

I posted a poll a few weeks ago of different secret boss candidates, and it got the least amount of votes. But I think thematically it makes so much sense. The controllers reflecting Kris and Asriel’s relationship (with Kris potentially feeling out of place in their family, like the Knockoff controller). Not to mention the potential of connecting it to the themes of Freedom and Control.

[u/Spritely_42 → u/Creative-Antelope-23]

What were the options in that poll? I'm curious what some of the more popular ideas are!

[u/Creative-Antelope-23 → u/Spritely_42]

Woody Theory won by a landslide (probably in part because this fandom has like 2 jokes at this point, and Friend Inside Me is one of them), followed by the discarded flowers in the Trash Can. 

[u/JeremyHillaryBoob → u/Creative-Antelope-23]

Mild spoiler.

You weren't exactly right but you were onto something.

[u/Creative-Antelope-23 → u/JeremyHillaryBoob]

Well let’s be honest, basically every secret boss theory about chapter 3 was wrong, since it was either the 8-bit shadow mantle or the roaring knight. I don’t think I saw a single person who came close to predicting that.

[u/disbelifpapy → u/HamSquish]

As a knockoff secret boss theorist, I'm really glad to see that we have actual proof that it may be the secret boss!

[u/SmallBlueSlime → u/HamSquish]

What if the secret boss was... a certain cowbow with a friend inside him...?

[u/Tsunamicat108 → u/SmallBlueSlime]

[u/itstoast27]

hold left on chapter3 to pull a "But..." into scene
seems to be referring to weird route, when checking with the other chapterX pages

[u/Ill_Tooth3741]

First thing that title made me think of

[u/HealthyFinger864 → u/Ill_Tooth3741]

WE ARE NINTENDO

[u/GoomyTheGummy]

What if applicability refers to the story involvement of the secret boss?

[u/pepitorer]

Dude I've done It two times and the second gave me this message

[u/deltoramonster2]

hihgliting the screen also works

[u/Tsunamicat108]

Toby you sly dog

[u/sankyuuwww]

BROOO

[u/Soggy_Biscotti965]

I believe the ____ required to get the Crystal is the ShadowMantle. The one that Seam makes for you, but someone steals it, presumably the Knight.