I have an annoying problem when I'm using the chrome browser on my Samsung Galaxy S5 (and also on Chrome on my laptop) . I will be browsing the internet (usually when reading an article of some sort) and the browser will redirect to another page that has a competition on. It's a different one every time and it happens seemingly randomly (sometimes I can view a page OK, other times I get the redirection). And then it won't let me leave the page by hitting the "back" button - I have to close the entire tab to make it go away. The most recent one I got is in the attached screenshot of my phone.
What is this thing?! Is it a virus? Ransomware? How do I get rid of it??
Any help, much appreciated, thank you!