ooh okay i've definitely talked abt this one before, because i started it back in (checks notes) 2019 lmao. i still like the concept a lot so i haven't completely scrapped it yet, but i doubt it'll ever actually get written. sadly
the gist of it is: sokka buys a wolf mask in ba sing se and, feeling restless and frustrated, starts taking up vigilante work during the night. until one night he runs into the blue spirit, and from there they form a sort of uneasy alliance, which eventually turns into a proper partnership, and the two of them become vigilante buddies, teaming up together to fight crime :)
Sokka glances back over at the others, still in a deep sleep across the room. Toph is snoring loud enough to wake the dead, and Aang and Katara are—gross—spooning each other. If he leaves now, and is back before sunrise, they probably won’t even realize he was gone…
He makes up his mind.
Tying the straps of the mask comes naturally, like it’s something that he’s been doing his whole life. Then he tiptoes around the room, pulling on his clothes, trying to be as quiet as possible. He grabs a nondescript cloak, courtesy of the Earth Kingdom’s hospitality, to ward off the night chill, and, after a moment of deliberation, grabs his boomerang, too.
As he makes his way to the front door, he catches sight of himself in the mirror and almost snorts. He looks like a criminal, dressed in all black like this, his boomerang slung over one shoulder and a wolf mask covering half of his face. Sokka bares his teeth at himself in the mirror, and then chuckles quietly, pleased. The mask really is perfect.
With one final look back towards his slumbering friends, Sokka slips silently out the door, unnoticed.