https://www.techdirt.com/articles/20190627/10152342486/nintendo-does-nintendo-mario-royale-fan-game-becomes-dmca-royale-is-now-dead.shtml

I've often made the point before that Nintendo hates you, dear Nintendo fan and general gamer. Between taking down fan-made levels, fan-made games, and going to war with all the ROMs everywhere, Nintendo values an overwhelmingly tight grip on its intellectual property rights far more than the natural desire by its own fans to express their fandom. The speed and reliability of Nintendo's lawyerly involvement has become something of a legend on the internet, with folks that make these expressions of fandom often joking upon release that it's only a matter of time before the suits come calling.

This held true with Mario Royale, a delightfully simple little web game created by a fan that allowed players to play through Mario Bros. levels alongside up to 74 other simultaneous players. The classic game had never been used for this sort of thing and it was quite interesting to watch how it all worked. It's also worth noting that the game was playable for free, meaning there was no commercial aspect to it. Despite that, you all know what happened next.