au where Jason is the one to deliver Damian to Bruce but he and Damian get into an argument on the drive over about how good at stealth missions Damian is and it ends in Jason double-dog daring him to skip the whole 'introduction' aspect of going to live with Bruce and instead to just sneak into the manor and see how long he can go unnoticed for.
Damian's claim is that the manor is so big and Damian's so good at remaining hidden that he could live in the manor without anybody else there clocking him easy. Jason just wants to see how long he can actually go because in his mind the longer Bruce goes without realising he has Damian in the house, the funnier the reveal will be. he's actually kinda rooting for Damian purely because it's funnier if he pulls it off for a really long time first. then Jason can snitch on him and the fall-out will be glorious.
he lasts about four months.
two weeks in and Alfred becomes suspicious, but chooses to believe that it's raccoons or pigeons in the attic because then he doesn't have to get involved. and he really doesn't want to get involved.
a month in and Damian almost gets caught by Tim while trying to steal some food in the middle of the night and getting cornered in the kitchen, but Tim hadn't slept in three days and was high on cold medicine at the time so he assumed that Damian was actually a hallucination of Bruce as a child, and all he did was stare Damian directly in the eye and solemnly tell him 'never ask your parents to go see a movie with you.' before going to pass out in the study.
two months in and Damian has gotten into a rhythm with it. feeling unchallenged, he starts waiting for Bruce to fall asleep in front of the batcomputer during hard cases so he can sneak out from the walls and fix whatever Bruce is getting wrong and solving the case before he wakes up.
three months in and Dick runs into him while sneaking in through a side door so he can grab some stuff from his bedroom without having to talk to Bruce, but Damian bullshits that he's one of Tim's school friends visiting to complete a school project, and Dick gives him twenty dollars to promise that he won't tell anybody Dick is in the building.
four months in and he gets cocky; starts ordering packages to the manor addressed to himself. Alfred asks Bruce at the dinner table why they've received an amazon package for 'Damian Wayne' and nobody knows what the fuck he's talking about. the next night the Red Hood snitches and asks how 'Damian's doing' and Bruce becomes convinced that Hood has the manor bugged. demands a full sweep of the building. Tim comes across Damian napping in a hammock in the attic wearing Tim's presumed-lost clothes next to a pile of supremely confidential files stolen from the batcave.
Damian wakes up and promptly tells them all that they aren't allowed to be mad because the statute of limitations for breaking and entering has passed already. Jason laughs so hard he cries.
