A music player for "The Most Mysterious Song on the Internet" (also known as "Like the Wind", "Blind the Wind", "Check It In, Check It Out" or "Take It In, Take It Out" after verses in some fan-interpreted lyrics). Most likely composed in the 1980s, whose origin, author, name, and original record date are unknown.

The song was recorded from a Norddeutscher Rundfunk (NDR) broadcast at an unknown date (widely speculated to be in late 1983 or 1984). Since 2019, this song has been the subject of a viral Internet phenomenon, with many users of sites such as Reddit and Discord involved in a collaborative effort to search for the origins of the song.