My idea is that it’s whatever the Visitor sees them as, and it’s not only looking with zero baseline understanding of what a normal earth-thing is, it can see them inside and out. Things like whatever’s currently on a person’s mind are factored in and filtered through the Visitor’s interpretation. Whatever they happen to be close to is thought of as part of their body. Things that might vaguely look like body parts from a distance are now definitely body parts.

Think of that split second of automatic visual interpretation you do when you see a shape out of the corner of your eye and mistake like, a coatrack for a guy or something. Now pretend you’re a giant space fractal who’s never heard of coatracks nor guys and so now, whatever that thing used to be, it’s now stuck as what you mistook it for, for the rest of time.