Au where the Fentons and the Waynes are cousins, not close but like 3rd cousins. Still, one day Jack is looking through old family memorabilia and sees a single picture of Bruce, immediately he’s like let’s go visit!
Cue impromptu trip to Gotham! And luckily, and I do mean luckily, Jazz looks up the family on the way and has to viciously remind Jack not to mention the parents that Jack did not know were dead.
No dear, not even as ghosts.
And when they get there, Bruce is surprised by the ‘random family members’ but Alfred says it’s true, they’ve met once before as children.
And Brucie Wayne comes out in full force because literally there is a living source of prime material he can use at the next gala just traipsing through his house.
And the Fenton kids are wholly expecting to bond with the Wayne brood about their ditsy, himbo father. And the Waynes are like no Bruce is actually smart, it’s not like a shared family trait like you think-
But the fentons are like:
Danny and Jazz: yeah, Dad’s smart about specific stuff. Just deep, deep, DEEP, down. But he’s pretty obsessive about one or two things.
Danny: yeah, you mention ghosts or fudge and he’s just whoosh, gone.
Jack, running from the other room: FUDGE GHOST?!
Jazz: No, dad just talking about you, you can go back to the kitchen.
Jazz: So what about your dad?
Bruce, randomly entering: Was I needed?
*cue collective spittake*