A really odd thing happened in Win 10

[Elixer]

Was basically moving files around form explorer to another program, when all of the sudden, this appeared.

That was rendered on top of everything.
Explorer wouldn't respond at all. It did not say "not responding", it was just frozen.
Couldn't move the window, could close the window, couldn't do anything.

So, now, killed explorer, and re-ran it.
Explorer was back to normal, however, that symbol was still in the same location, and, again, on top of everything, so you couldn't see what was behind it.

The only thing that made it go away was a reboot.

Now, what the heck is that image used for?

 

[BonzaiDuck]

I'm only guessing in a fog. There has been a lot of news about Wanna Cry Virus. However, that latest scourge was ransomware. It would've been demanding cash from the beginning.

That's one possibility. After that, I'd begin uninstalling my video driver and look at your desktop configuration carefully.

Somebody else must have seen that screen before.

 

[Ketchup]

I think you are seeing two different oddities at once:
1. Explorer froze.
2. The image didn't leave the screen.

As for number two, I encountered that one on my VM last week (10 with CU). It was a pop-up message from a web page that would not go away until I rebooted at the end of the day. I couldn't tell you if it was a graphics issue, a browser issue, or even a Windows issue. Haven't seen it since either.

Will be interesting to see if anyone else has similar experiences.