Damien saying "I know a guy" but it's just Marinette in various costumes
I have this idea that won't leave me alone, so I thought I'd share it so that others may be cursed with thinking about it too.
(This can be read as either sibling or dating Daminette)
Damien is all grown up and joined the Justice League as a permanent hero. Everyone knows he was Robin, so they think there won't be any surprises. Until there's a big mission and they need to infiltrate somewhere and plant cameras for evidence (or something). However, this place is a fortress (like the best anti-hero security money can buy) and the only way in is through the vents which are too small for humans to fit through.
The Justice League meeting turns into one big loud argument. Until Damien says, "I know a guy."
Obviously, he's very dodgy about his contact, but he says they can be trusted. Since, he's Robin, they let it slide.
The Justice League is all waiting at the contact spot when Marinette pulls up. They're confused, Damien is light-tipped, and she's in her multimouse ensemble looking all cute.
Marinette pulls off the mission then dips and Damien is stubborn even when Batman questions him. (Could be either good parent or bad parent Bruce Wayne).
Eventually, they let it drop. Until another big mission happens and they need a specific skill set and Damien says, "I know a guy." Cue Marinette with a different miraculous.
The Justice League assumes all the girls are different people and they're very confused like, "Robin, where do you keep finding these girls?"
Cue lots of half thought-out shenanigans