Super Smash Brothers Ultimate - ProsafiaGaming

1. Find a ProfasiaGaming video in your related videos or recommended for you sections
2. Click its drop-down options menu next to the thumbnail, and choose "Not Interested"
3. Click "Tell Us Why" and choose "I'm not interested in this channel: ProfasiaGaming"
4. Rejoice in never having to see their videos again without actively searching for them

I don't know who this ProsafiaGaming is, but agreed, people who do that are absolute dicks.
There was also the time where a Pokémon YouTuber called Xeogran put Ultra Necrozma in the thumbnail of one of his vids A WEEK before Ultra Sun/Moon came out.