I see a decent amount of people portraying Dust's brother as either his hallucination, or a literal ghost. But what if it was a mix of both?
As in, he'd have his usual hallucination of Papyrus, but along-side it his ACTUAL brother would just hover over his shoulder, like "No, that's not me, please stop." Though it would be in a sense where Dust can barely tell the difference. It's not like he can really touch Papyrus to get a sense of if he's real or not.
But because of his existence it might give Dust more evidence to believe his hallucinations. "Oh if Papyrus IS actually real, what if the rest of my hallucinations are too?" Or "Did Papyrus actually want me to do that god awful thing or am I just imagining it." Sort of instability.
I think it would be an interesting concept to play around with.
