The car was almost the last straw.
Obito is pretty sure it would be for almost anyone, because honestly, they flew a damned car into him just as he was settling in for the winter, and it hurt. It was also rude, and Obito was well within his rights to hit back.
Well. Not that not having the right has ever stopped him before.
Still. The car was close to the end of his patience, and then the broom was insult to injury. The dog crawling around under his roots, dragging children along with him and making them scream and waking Obito up?
That’s so far past the last straw that Obito doesn’t have words for it.
For the first time in centuries, for the first time since he landed in this dimension and decided fuck everything, he was going to pretend this was the afterlife if it killed him and turned himself into a tree with a desperate bit of Mokuton (an angry tree, but what the hell, that was half the fun), Obito decides to be human. It’s about as simple as that, after so long; a moment of will, a burst of irritation, and he rips up his roots, takes a step, and drops down into the shack some enterprising asshole carved out under him years ago.
“What,” he snarls, “the actual fuck are you doing?”
The dog-man stops dead, in the middle of hauling a kid into the room. The kid’s cries cut off, and he scrambles back, dead-white, dragging a broken leg. Obito spares him a glance, but doesn’t stop, stalking right up to the gaunt-looking man and stabbing a finger into his chest.
“I was fine with the car,” he snaps. “I was okay with the broom. But I lived through you assholes swanning around under my roots and shrieking and howling once a month for seven years already, this bullshit is not happening again, do you hear me?”
“What?” the man asked, dazed. “You—you were a tree? You were the Whomping Willow?”
Honestly, Obito has been called worse things. “Yeah,” he growls. “And I’ll fucking prove it if you don’t cut this shit out. Let the kid go—”
A rat scrambles out of the redheaded boy’s pocket, and the dog-man lunges. Obito shoves out a hand before he can reach, and a whirl of warping air drops the rat right into his hand.
“You,” he says dangerously, narrowing his eyes at the thing. “You're the one who kept hitting my fucking funny bone.”
The rat squeaks in terror.
“That’s Peter!” the dog-man says, scrambling upright. “Don’t—I have to kill him—”
Obito rolls his eyes, holding the rat up by the scruff, but before he can do anything there’s a shout from behind him. A boy with scruffy dark hair and glasses stumbles in, a girl with bushy brown hair a step behind him, and Obito has definitely seen them before. Suddenly the redheaded boy is a lot more familiar, and Obito growls, points a finger in the dark-haired boy’s face, and says, “You! You're the one who hit me with the car!”
“Er,” the boy says, caught off guard.
“Scabbers!” the girl says, and she takes a sharp step forward, hesitates.
“Harry!” the redhead warns. “Harry, the dog, he’s an Animagus, he’s Sirius Black!”
“What?” Harry jerks twist—
Obito catches him by the shoulder, propels him over to his friend, and the girl scrambles after him. “Sit down,” he snaps, and then waves the rat. “And you, you’d better stop looking like that or I'm going to show you just how carnivorous some plants can be.” To add weight to his warning, he holds out a hand, and an oversized Venus flytrap surges up from the ground, jaws gaping.
The rat squeaks desperately, thrashes, twists, and the redheaded boy shouts a denial. He scrambles up, but Harry and the girl tug him back, and in the same moment the rat shivers, twitches, changes.
Obito drops the balding man to the floor with a sound of disgust, wraps branches around him like iron bonds, and drags him up against the wall of the Shack.
“You're an asshole,” he tells the shaking man flatly, and with a delighted meow the big orange tabby cat leaps onto the rat-man’s lap and sits there, purring menacingly. Obito glares at it, and says, “Watch it, you're on thin fucking ice too, you know.”
The cat blinks innocently at him, unbothered by the accusation. Obito honestly doesn’t know what he expected.
“What?” Harry says, and wide eyes shift from Obito to the rat-man and back again. “I—what?”
Sirius laughs, hoarse and vindictive. “Harry,” he says, and his teeth are bared in a death’s-head grin. “Meet the man who betrayed your parents.”
He’s obviously got a sense of the dramatic borrowed from an Uchiha, Obito thinks. “You're shutting up, too,” he warns Sirius darkly. “Sit down, shut up, and maybe I won't turn you into fertilizer—”
The door bursts open in a shower of red sparks, and another familiar man steps through, wand raised, face pale. He pauses, mouth dropping open, and then says, “Peter! It’s true—”
“Oh, fuck all of you,” Obito says, and buries them in vines, pinning Sirius and the werewolf and the rat-man to the wall with no chance for escape. “Someone start talking, and you’d better have a damned good reason for all of this utter bullshit.”