Closest thing I can compare it to would be a contrail dissipating in the moonlight. Just saw one doing exactly that minutes before typing this so it's fresh in my mind. But instead of an aerosolized mist, the light sources were distinct white 'twinkles', sort of like what one sees with a meteor tail, and seemed to be on an emission spectrum as opposed to being reflected from or transmitted through matter. There was a defining line that remained distinct as the light sources dissipated along and mostly below it, and there wasn't any observable movement associated with it. The definition of the line/edge reminded me of how a high powered laser appears against a dark sky. It was as if the 'twinkling' defined the edge of an object I couldn't see were it not for the light next to it. Possible it could have been another contrail but the 'twinkling' lights were different than a mist, like how I'd imagine Tinker bell's wake might appear as she flew by. I would describe the dissipation of the 'twinkling' itself similar to something losing energy in a hurry, like a glowing piece of metal cooling, not in the glow itself but how the glow disappears as an object cools. The time I first saw the 'thing' to when it was no longer visible was 5-7 seconds, called my wife out for a look but she wasn't quick enough.

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