@WendyForbes This looks like a double exposed pic, like the data for two pics got combined and written to the same file. The upper arms are translucent compared to the legs. I'd guess someone with long hair walking by, perhaps more toward the camera vs. perpendicular. That and the low light camera using longish exposure or doubling up data into one file. It's a bit easier to see in the larger pic on the site.
@RileyNorman I just knew someone on here was going to blow up my skinwalkers are real theory. 😆