using a reputable tool like Malwarebytes or Windows Defender if you attempted to open the file.
It is almost certainly an executable (.exe) or a script disguised as a video. Delete it immediately if you have already downloaded it. Willow.S01E04.720p.WEB.h264-KOGi.mkv.mp4
Genuine video files do not have double extensions like .mkv.mp4 . This naming convention is a common trick used to hide the true file type from users who have "Hide extensions for known file types" enabled in Windows. Why this is suspicious: using a reputable tool like Malwarebytes or Windows