Deltarune theory using evidence from chapter 5, thus spoilers. Egg Man + Gaster + Shadow crystals, all addressed in one theory. Kinda.
(update. This turned into a major ramble. Skip to the last 2 [Edit:3] paragraphs if you just want the base theories ig. This is really long. I wrote it AS I was figuring it out.)
Okay so I'm gonna sound slightly crazy for saying this with such little evidence.
The shadow crystals are gonna let us meet the egg Man. Who is also gaster. Who also might be Seam.
.... Wait. That's not right.
The eggs. Will help us. Fight? Gaster? Who is also seam. And still the egg Man.
No, no that doesn't make sense.
Okay. Okay, let's. Start from the beginning.
Seam, in chapter five, after explaining the crystals, says "I am aware of something we can do with them. Something very, very interesting."
Very, very interesting, huh? Now why does that sound familiar.
I wonder.
Anyways, he also says-
Wait. I think I figured it out. Okay, okayokayokay stay with me here I'll explain the conclusion as the conclusion.
Anyway, he also says that the next enemy, the next shadow crystal, will be the last. Meaning whatever we can do with the crystals, we will only be able to do in Chapter 7. The last chapter.
Asgore also, at one point, uses the words "very, very interested", and if you look at the egg in the overworld it says that something "very, very bad" will happen if you throw it away.
Now. I can't exactly... Go into full detail. About this next bit. Because it'd be so many paragraphs and because I'm afraid of forgetting my conclusion by the time I get to it. But there's also a theory that Undertale was, in fact, an old Dark world. How does Frisk come into that? Don't know. The goners? ¯\_(ツ)_/¯ What about Asriel, Flowey, Jockington/Catti=Friend theory, Friend in general, is that why people keep using G on accident, Titans, Darkners/Lightners, what about-
Look. I don't know. I just know there's EVIDENCE. And a lot of it. And we're running with it. It said Undertale was a PARALLEL story. It COULD be the story of that Dark World, but changed in certain ways. It could be that after the monsters escaped, the humans trapped them all in the town instead of underground, in the dark. I DONT KNOW. But we're running with the UT-DarkWorld theory/evidence for this. Anyway.
... Shit, where was I going with this?
Uhh. Anyway. The man behind the tree is, at one point, mentioned as having an empty palm. Empty as in missing? When you insert 1225 into the ball machine, it takes away your palm. After drawing the man, Kris paints over it all with a tree. Perhaps there's an argument to be made about Kris seeing Gaster lure Dess behind a tree, then disappearing, but like. Who knows.
Holy shit, I've like completely forgotten. One sec. If I say enough evidence, it'll come back, I swear.
We know now, that the dialogue we get from interactions comes from Kris, even though there was evidence for that in Ch.4 as well. That means it's KRIS who says something very, very bad will happen without the Egg. The shadow crystals make something "very, very interesting." At the end of the Weird route, it changes something in the master file of the game to log that you completed it, "_b".
If you get something "very, very interesting" only AFTER chapter 6, it means at chapter 7 is when it will come in use. Y'know. "Insert chapter 7 side b".
If you do the sword route in chapter 3, you originally could get the egg. That was, until there was an update that allowed you to go to the ball machine, find the ticket THERE, and get another pink and yellow controller. Despite being used up, a FRIEND colored controller appears. (Another?)
It's as if, you weren't originally intended to get both. It's as if to do so, you need FRIEND.
The sword route, seemingly intended as a tutorial to the Weird Route, locks you out of getting the egg— wait.
"you're unsure how many dogs this counts as". Spreading the eggs. Deltarune.com/egg. Are the eggs gonna end up creating multiple FRIENDs?
Back on track. Old Dark World, Gaster allusions, blue Goner, G, "Very, very interesting" = Ch.7, RIGHT, I REMEMBER, "Something very, very bad" from throwing away the egg.
In chapter 7, we visit the original Dark World = plausible
In chapter 7, after getting all the eggs, FRIEND, "always at your humble service" appears to help us FIGHT gaster. Which is why throwing away the eggs it comes from results in something "very, very bad".
Prrrrhaps, as FRIEND seems related to Noelle, likely bc she might have been the first time it was even brought into existence, via Cat Petterz, in Side b there's something important happening between it and Noelle.
Oh, also, I think the original Dark World is underwater. In the lake. Onion-san heard singing from there. If they go to the original dark world in chapter 7, and side b is after Noelle and Kris walk into the lake, then perhaps side a is the usual cast, and side b is Noelle and Us/Soul. Also, "Raise up your Bat" being in an underwater area + the singing, perhaps Dess is down there?
Look. I'm never right. I've stopped trying. I'm just spit balling. It's gotten to the point where the "Friend Inside Me" theory, the ONE theory I hadn't taken seriously, was the SINGLE most correct one, while all the others I believed were PROVEN wrong. Your best bet for the survival of your theories, is keeping them out of MY, SPECIFIC line of sight. I'm like a curse upon mystery games.
Anyway, to sum it up: in Chapter 7 we meet (and fight?) Gaster in the original Dark World, which is also kinda Undertale, and at the bottom of/at the other side of the lake, The soul MIGHT split from Kris into the Vessel (see: MewMew/Pink) and in Side_b it will be just Noelle and Us, while in Side_a it will be the usual cast. Also Dess might be there and we might summon ___ (colloquially referred to as FRIEND) to return to being at our "humble service", or at the very least Noelle's, but those two are a bit less likely.
(side theory: after telling Kris they'd investigate the song, Striped Bird says "wait, don't!" A lot, W.D, W.D, wait, don't, perhaps, or don't wait, or both, Susie can hear the song in chapter 4, and in chapter 5 the bird is selling dough balls that taste like onion, and tries to sell them for G. I'd say Gaster absolutely kidnapped Dess, killed onion and turned them into dough balls to prevent investigation, and tries to use G because Gaster has been partly been controlling them and forgets that's not the currency. Perhaps the "wait, don't" was the striped Bird saying "W.D, wait, don't!" And Gaster saying "don't wait." As in don't wait for Onion, they won't be coming back. Prrrhaps, the song was intended to get Onion out of the way so we and Noelle could get to the Dark World uninhibited and uninterrupted. Just a side theory.)
(SHIT. EDIT. FORGOT ONE THING. THE SONG MIGHT BE DONT FORGET [For some reason I remember "aren't you forgetting something?" Being said a lot btw] AND IT MIGHT BE DESS SINGING BUT WHO KNOWS THATS PROBABLY TOO FAR)
Okay I've been doing a lot of updates I know but let me add one more:
His name is "Striped Bird". It specified bird. I've heard people saying—and I think I agree—that the striped Bird is a PARROT. That him saying "Wait, don't" is him parroting back Onion's last words.
Perhaps the "it's only 2g. It's only for free." Was Gaster telling him to go "it's only 2G" then remembering they don't USE G, and having to correct himself, thinking it would only say the last bit.
