That's troubling. If your S6 is running Android 5 (Kitkat) or higher you should be able to disable specific applications from a settings page.
To view all of the applications on your phone, open the Settings app. Once that is open, look for the option called "Applications" or "Apps". This settings page should give you a list of all of the applications installed on your S6. If you find anything suspicious you can tap that app and on the next page have the option to uninstall, force quit, or disable the application.
Since you don't know the name of the application, I'd recommend viewing Settings -> Battery and looking at the list of applications that use the most battery. You can also open the Play Store app and view My Apps and Games from the sidebar and look at the recently updated applications.
If you discover the name of the mystery application from either of those you can go back to the Applications settings list and uninstall that specific application.