Its Adware from new free app you or a virus installed. To get rid of it press on the app for few seconds. Once it stops you should he able to see the icon of the app and then just get rid of it.
Hit the recent apps button/icon/gesture when it pops up and see what app is showing that screencap of that pop-up. I've discovered many a bad app that way. Still looks like one of Cheetah Mobile's little 'perks'