ok so im going to assume that, since you said we have to guess, we ARE going to find out what karkat was reminded of... i like the way you think (also i have 1 guess buts its mostly wishful thinking rip. act 8 is the only canon i need anymore)

I don’t want to overstate the significance of this mystery, but the clues are all already here. I mean it when I say I want to hear your guesses though, wishful thinking as they may or may not be. (And what do we know about wishes and dreams other than that they’re awesome, anyway.)