Dipper and Mabel cosplaying or dressing up as the stan twins for summerween or Halloween.
Dipper as Ford and Mabel as Stan.
Dipper wearing a long coat, a red sweater and glasses similar to ford’s. Carries around a fake journal(since the real ones are burned up now)
Mabel making a fez that fits her head better or just stealing Stan’s. Same with the cane. She wears a suit and has the same kind of tie.
Or it could be vise versa.
Mabel as Ford with a giant coat on and she flops the sleeves around a lot. She wears one of her red sweaters she made herself. Gets some glasses and carries around her grappling hook, yelling “FREEZE!” at any and all children dressed as monsters.
Dipper as Stan, wearing the outfit he had in “boss mabel”, but now with a fez and cane that Mabel helped him make.
Ford and Stan are touched, Stan takes a crap load of pictures.