This app was mentioned in 5 comments, with an average of 1.20 upvotes
This worked perfectly, thank you! I did this and was finally able to see the name of the app, which was surprisingly Avira Antivirus.
I've been using Avira as my primary desktop Windows antivirus software for years. I'm done with their products after this incognito adware experience.
Looks like a floating action button or whatever these things are called in the android docs. You should be able to remove it by holding it down and dragging it to the bottom center of the screen where an trashcan or x will appear.
The s5 mini has an ir blaster to act as an remote, and it has some bloatware remote app installed by samsung i think, so by disabling/removing that app the icon may disappear as well.
If you can't find a remote app and can't remove it as described above, try downloading a mobile anit virus app, like avira mobile and perform a scan
If you want to wipe your data remotely, Avira offers this service. I don't use the app itself, but I did beta test it and I have been a desktop customer for over a decade now.
Avira anitvirus is good: https://play.google.com/store/apps/details?id=com.avira.android