For about a month, an unknown app has been occasionally coming up on my cell phone's screen, interrupting whatever I'm doing, displaying a black screen and that rolling circle in the middle that means I should wait.
It lasts a couple seconds or more, then leaves without a trace, returning focus to whatever I was doing before.
When it lasts a little longer, I'm able to press that lower-left button that "zooms out" to all open apps, each with its logo on the top. I'm then able to close it, or take a screenshot.
The logo of our mystery app is a red-and-white megaphone, which I do not recognize. See attached screenshot.
That logo does not appear in the list of all installed apps.
The timing seems to be random.
What is this app, what is it doing, and how do I get rid of it?
The phone is a Samsung Galaxy S9+
I'm running Android version 9
The phone has served me flawlessly for over a year before getting this issue.
I do have many apps installed, some of which are ad-supported games. They all either came preinstalled, or came from the Google App Store.