I wonder if these little things literally move on their own. Kinda like how like Venus flytraps have traps that can close when triggered by an insect (or a curious child), or how some parasitic vines will try to mimic the leaves of their hosts even if the host is artificial. Is it possible that moss’ leaves just subtly move during the day, and because we’re talking about moss balls, that subtle movement translates into physical translation? Granted, it doesn’t explain why they move together, but if you can figure out the mechanism behind the movement then it’ll make it easier to figure out the rest.