Avast started pinging really quickly about three times, then I got a legitimate-looking message about Adobe Flash Player update. The Avast popup said that there’s a problem in my AppData\Local\Temp folder. This update is also in the same folder.
I try to close it repeatedly, but it opens again. Eventually it disappears into the background as the flashing notice.
I scan the folder and it finds no threat. However, this has happened yesterday and today around 11:30 PM, so I doubt it’s actually gone.
Starting a Malwarebytes scan now, not sure how long it’ll take.