Mike isn't a joke. He's real. And he'll appear in Chapter 6
Mike as a lightning rod for theory crafting dropped off after chapter 3 came out and had the battat trio messing around, and that's fair. The battat trio was clearly meant as a little playful jab at theorists, for a very good reason. Theorists cook up some INSANE shit from time to time and really over play certain ideas that probably started out as jokes and stop being treated like jokes really fast.
But I think too many people dropped wondering who mike was a little too fast.
Because I don't think toby was telling us to stop, just the opposite
He wanted us to keep looking.
So I'll keep looking
So what I think the main thing we got right was Mike is a Microphone. Ok! but there wasn't any Microphone in chapter one and two. Was there?
Well... no, BUT there was someone who was known to sing in chapter one
Asriel. We know that Asriel and Dess were in a band together.
I also think the little band mini game could be a hint. Kris is on guitar, and ralsei is on the mike, while susie plays the drums. (if I remember correctly, pizzapants played drums in their band, but I can't remember where I heard that)
In addition to that, Dess kept a lot of things of Asriels in her room. Like his retainer and one of his shirts.
But something else she could have kept of his was his Microphone
This microphone. This is Mike.
I'd also like to point out another funny little detail that might tie ralsei to asriel in the band minigame specifically. Their hair.
ralsei is sporting an especially silly mowhawk in the band game.
and if we look in the flash back sequence tenna has
it might not be clear, but there seems to be a little bump like shape on asriels head. It almost looks like a Mowhawk. And considering he hung out with Dess it wouldn't be surprising if he got one to impress her.
So we're going to meet mike. In Chapter 6. Which will be the holiday house. It wont be anywhere else. It wont be the hospital and it wont be the Bunker.