One of my fave batman concepts is bruce taking time, very rarely, to be a mischievous mf towards league members. It’s so cathartic to just. Fuck with them a lil bit. He can be petty as a treat. They’re not necessarily pranks but not.. not pranks. But his sense of humor is so dry half the time it comes off as a threat & nobody EVER suspects him.
why do i imagine the batfam finally meeting the league and then one of them going 'how the fuck do you have so many kids?' and little shit Jason goes 'well, when two people love each other very much...' and because Bruce doesn't wanna listen to this, he tiredly reminds Jason: 'you're adopted' which naturally means that Jason is going to dramatically pretend that this is the first time he's heard that and how could Bruce keep this from him, much to the horror of the league and the exasperation of Bruce
Let’s amp up the “Jason says ow and the batfam thinks he must be gravely injured” headcanon.
Jason calls Bruce or Dick for fun and says nothing but “goodbye” before hanging up (maybe it’s a dare by Roy who TOTALLY suspects the reaction Jay is gonna get).
Ten minutes late the entire Justice League is scouring Gotham, on the hunt for Jason.
During a press conference for the newest Justice League member, Phantom, a reporter asks him "Do you have anything to say to all the children who aspire to be like you?"
Phantom looked at the reporter puzzled before saying, "Children wanna be like me? Why? I'm a bad influence."
My fave habit to headcanon is Dick pulling on the ears of the Batman suit. Like, it's something he started as a kid, when he often landed on Bruce's shoulders, so he could get the man's attention and he just kept doing it. And then I imagine newly recruited Justice League member Nightwing tugging on Batman's cowl ears to get his attention for something and everyone just staring bug eyed at why Batman isn't exploding at the disrespect (bar the few that knew Dick when he was still an excitable kid, those are suddenly hit by the fact that that kid is all grown up now) (not B, though, whenever Dick does it, he just gets hit by a wave of fondness and nostalgia, bc it doesn't matter how much time passes, Dick is still his kid, his baby).
More than half the League is betting at any time that they know when it's actually Batman under the mask, or someone else. Unfortunately, they were wrong when:
Dick was doing a phenomenal job of playing Bruce (didn't give himself away even once by smiling), because he fell asleep
Batman stubbed his toe against a table and swore like a sailor which led to cash exchanging hands as several people figured it was Jason, but Bruce had recently switched out of Matches Malone to dress up as Bats and hadn't shaken the Mindset yet
Batman's suit sat weirdly empty at the table and Oliver, annoyed, tried to tell Damian that this was too serious a meeting for Bruce to delegate, but it was Batman, hit with a de-ageing spell and too stubborn to sit out
After sustaining pretty serious injuries, Batman was whiteknuckling the table, in an awful mood, and nobody thought anything of it. Barry offered to help Bruce up (if the pain was keeping him trapped, trying not to insult Batman too much), and Jason tightly replied that if he moved the suit was going to tear.
Clark and Bruce had a bet for how long they could replace Bruce with a mannequin without anyone noticing, and because Clark kept looking over at "Bruce" and giggling (pretty par for the course for them), nobody noticed for five hours.