Reminds me of Mobicow ads, that cover the entire fucking screen on a mobile, don't have an obvious "fuck off" button, and aren't a separate page so the back button takes you away from the site, or closes the browser if you got there as a link from a different app.
They were in use on a popular meme site a while back. I never managed to see the actual pictures when the fullscreen bullshit came up, and was glad when Reddit blocked said meme site for unrelated reasons