I think about this a lot, because for me personally, a lot of the Snape-takes-Harry stuff in first year bleeds out a lot of the canonic personality we see Harry having, and so he’s way more skittish, he doesn’t talk back, he’s frightened of everybody, etc; at the same time, Snape often ends up like, having a relatively easy time of letting Harry’s home environment overwhelm his natural ire of Harry and what he represents, and like…
So I can see like, the start of it, and just Snape with Dumbledore, arguing with him that McGonagall does most of the first year welcomes, that Dumbledore knows he doesn’t like the kids anyway, he isn’t good with children, he isn’t welcoming, and Dumbledore who is just serenely like “No, Minerva has other stuff to do, and the boy hasn’t been responding to his Hogwarts letter…”
And being as Dumbledore is the way that he is, I can completely see him quietly implying that there’s some kind of risk involved, that Harry is obviously under threat because he’s been removed from Lily’s protections and taken off to this weird island, so…
Deeply frustrating, as ever, that Dumbledore knows how to push Snape’s buttons, but the buttons are pushed, and nape goes like, immediately. The way Dumbledore says it, he probably implies that it’s someone else who’s taken Harry to fucking Craggy Island, so Snape arrives completely silently, under a Disillusionment Charm, and you just see like…
Harry, on the floor, awake, staring at his shitty little digital watch, and the latch on this big door silently lifting, the door moving so slowly and so deliberately open, despite the fact that the wind is utterly howling outside, and Harry freezing, listening for something, but… Obviously, he doesn’t hear anything. He hears an inescapable silence that’s hidden under the storm, as Snape moves up the stairs and just checks…
Sees Petunia and Vernon sleeping in some uncomfortable bed, the both of them fast asleep without a care in the fucking world, curled up together under some blanket, no sign of any other threat, anything else…
And the thing is, Snape doesn’t want to talk to these fucking people. He doesn’t want to talk to fucking Tuney after fifteen fucking years since last talking to her, he doesn’t want to think about Lily, Lily then, before he fucked everything up, and so he turns on his heel, descends the stairs, and looks at Dudley, asleep on the couch, snoring, whatever.
And so Snape, almost completely invisible, looks at Harry, who’s now sitting up with his back pressed against the wall, and he doesn’t see like, an arrogant lad ready for anything, but crucially, nor does he see a terrified little child. He sees an eleven year old, small for his age, scrawny (and Snape was too, Snape was just like Harry, small and scrawny for his age and unkempt, but I don’t think Snape would be able to make that connection unless someone else nudged him toward it, because it’s just too painful and too self aware), and… Utterly silent. This boy, lips pursed, green gaze very serious behind those glasses, scanning the room and looking for something, plainly listening intently, and then he looks right at Snape.
And for just a second, just a second, Snape is looking directly into his eyes, those eyes, Lily’s eyes, and then he sees them carve the corner of his Disillusioned silhouette. Here, in the dark and dismal stormy weather, wind howling, likely having no practical experience with Disillusionment Charms and how to look for them, Potter sees the edge of the charm.
If he jumped up and screamed, if he demanded, “Who’s there?” I think that Snape would have just appeared, grabbed him, and dragged him out - probably kicking and screaming, so that would wake up the Dursleys, and then there’d be the whole thing, but I don’t think Harry would.
Harry sees the edge of the Disillusionment Charm, he sees the silhouette of this man in front of him - a relatively short, small man, yes, but still bigger than Harry is himself, and Snape sees it in his face, sees the slight widening of his eyes even though he keeps his mouth shut and his face as still as possible. And then he tries to pretend that he didn’t.
The movement between him catching the edge of the Disillusionment Charm and continuing to scan the room is not smooth, it isn’t practised, but it only lasts half a second and then he starts to scan the room again.
And that, that makes Snape take pause.
He very slowly sinks into a crouch, lets the Disillusionment Charm fade, and looks down at Potter, whose face doesn’t change, who stays very, very still. Snape sees his hands go to the edge of the blanket.
“Do you know why I’m here?”
“You haven’t been answering your letters, Potter,” Snape whispers, studies Potter’s face, watches it for any differences, certainly doesn’t miss the way he grips a little tighter at the blanket, getting it ready under his palms. “Too much fan mail to stay on top of?”
And Harry obviously has no idea what the fuck that means, but he says, “They won’t let me have my letters. Why, was it you who sent them?”
And that’s surprising, Snape is surprised, because he’s been watching this kid be deceptive, and he isn’t that good at it, not yet - yes, he’s smart, yes, he’s obviously practised at lying, but he’s still a kid, he’s not as good at it as he will be when he’s older, especially not when Snape’s whole thing is looking for tiny little hints in someone’s face… And Harry obviously doesn’t know what he’s talking about, doesn’t know who’s sent his letter.
“It’s your Hogwarts letter,” Snape says, just to check, sees the utterly blank incomprehension.
“I don’t know what that is,” Harry says, glances to the couch, where the other nephew is asleep, to the stairs, where the Dursleys are upstairs.
“Why is it, Potter,” Snape says quietly, “that you are lying in the dirt under that rag, with your aunt and uncle upstairs? What, precisely, is going on here?”
“Dunno,” Potter says, and Snape catches his wrist before he can throw the blanket over his face, before he can scramble back, and when Potter goes to scream, Snape’s hand is already clapped over his mouth.
He lets go of his wrist, reaches into his pocket, removes the envelope, holds it up so that Potter can see it, and when he removes his hand from Potter’s mouth, he hands him the letter. And once again, he’s surprised - Potter doesn’t snatch the letter and rush to open it, he takes it slowly, takes a step back, keeps his gaze on Snape, who arches his eyebrows and puts his hands up flat in line with his shoulders.
(His wand is in his sleeve, but Potter plainly doesn’t know enough about magic to know that.)
And Potter opens the letter, scans the page in the dismal light of the freezing cold little hut, and Snape can see that he’s shivering, that the clothes hanging up are still damp from the roaring rain… Potter’s lips are moving as he reads, and Snape can see how much he looks like his father, feel his teeth grit, but…
“You’re mad,” Potter says.
“Really?” Snape asks softly. “You’ve never done something you can’t quite explain, never found yourself abruptly in a place you didn’t mean to come to, never seen an object transform before your eyes? Never seen the shadow of a man you know can’t possibly be there, because it seems to your eyes that you’re looking right through him?”
“You’re from this school?”
“I’m a professor at Hogwarts,” Snape says quietly. “Potions.”
“Prove it?” Snape repeats in a whisper. “You want me to do magic?”
“That or show me your drivers’ license,” Potter says, and Snape is so caught by surprise that he almost laughs - is Lily’s wit really buried beneath Potter’s face? He’d love to call it arrogance, but even if it is arrogant, Potter is taking a slow step back and away from him, and honestly? Snape has had enough of this.
So he grabs Potter by his shoulders, grips them tightly, and Apparates them to Hogsmeade so that he can deal with the explanations there.
(And when Dumbledore meets them at the gates, he looks mildly displeased, but, and Snape hates this, not even a little bit surprised.)