Unfortunately that comes from an app you installed. The unfortunate part is that it's hard to pinpoint unless you know which app you've installed lately or has a bad rep for showing ads or know what has been updated. Only way to get rid of them is to uninstall the culprit app or, if the app has it, turn off that setting (some apps show that as a charge management screen or battery maximizer or something, but they only just show ads on top of your lockscreen).