https://www.bleepingcomputer.com/news/security/fake-adult-sites-pushing-unwanted-extensions-miners-and-adware/

Adware, PUPs, and unwanted extensions are being promoted through sites that pretend to be adult video sites. When a visitor tries to play a video, a fake video player popup will be displayed that states you must download and install an updated media player to see the video. This "media player", though, just installs unwanted programs onto your computer or redirects you to unwanted chrome extensions.

These fake sites consist of autogenerated pages based on popular celebrity or adult star keywords so that they can get as many pages as possible into search engines. When a user clicks on these links and tries to play the video, they are shown a fake video player like the one below.