Stranger Things. ** spoilers **

Maybe it's a crossover, and he'll turn up in ST4. :P

In ghost hunting lore (I did this) and even older movies (check out Sixth Sense), photography and videography of ghosts and paranormal activity is often associated with motes of light. As soon as I saw this effect I realized she was a ghost, which is why she could travel and appear at will. I thought it was very cleverly done.