Try something. Go to YouTube, and click on literally any video. The URL for that video will start with "http s://www.youtube.com/watch?v="
(I had to put a space after http to get it to display on screen here).
Remove the "h" from the word "watch".
WTF???
Yep, that is a head scratcher and creepy
this was in the comments
"Explanation of how this works: It's making use of 2 channels, 1 with a username of 666 and another with a username of watc. When you remove h from the url, it can't parse the query string (the part after the ?) anymore, as it's a query string for the watch url. So instead, it tries to open the profile with the name watc. YouTube channel settings allows you to set a redirect URL for a specific channel, so what this user has done is have the channel of watc redirect to the video uploaded by user 666. That's it really."
not sure if that all checks out or not, just reposting it