If i moved the screen, the little dot did not move, unless I placed my finger on it, in which case it WOULD move directly beneath my fingertip; if those movements were horizontal, the screen would move in the direction I was swiping; if my movements were vertical, the screen would NOT move (but the dot did, beneath my fingertip). Tapping the dot itself did nothing, unless the ?dot was situated over an interface element which normally would respond to a tap.

After a minute or so, the dot began moving spontaneously down the screen at a slow but constant rate (perhaps 5 seconds to reach almost the bottom, where it stopped). Placing my fingertip on it again, I was able to reposition it. So long as I didn’t swipe SO far horizontally as to bring up the previous or next icon page, the page would recenter when I lifted my finger from the screen.

I had many apps open; I thought perhaps it was associated with one of them, but running in dark mode.it might be impossible to tell, so I terminated all running apps one by one, noticing that it was a tiny bit different shade of black that the background screen of each of these apps, and it remained on screen after I’d terminated them all.

I took a screenshot, but the dot wasn’t captured in a screenshot of my home screen, so I opened my photos app, saw that the dot was still visible, so did another screen capture with a predominantly light colored photo, but it wasn’t captured on a screenshot of a photo, either. I selected another photo to capture, centered the dot on that photo, and then the little bug(ger) disappeared. It was still too early for dark mode to have auto converted to light mode. I cannot be certain that I didn’t cause the disappearance somehow by preparing to take the screenshot.

Has anyone else seen this? If so, WHAT WAS IT?