Base: Pokémon Crystal · Game Boy Color · 2016 · Total conversion
Creator: Koolboyman and team
An eight-year total conversion of Pokémon Crystal that received a cease and desist from Nintendo days before release — and leaked in full within hours anyway.
Pokémon Prism is the successor to Pokémon Brown, another Koolboyman project, and is a total conversion rather than a modification: a new region, a new story, new music, and mechanical additions the base game never had, including the ability to play as a Pokémon directly and mining and crafting systems bolted onto a Game Boy Color engine that was not designed to accommodate them. Development ran roughly eight years. The release was scheduled for December 2016. Days beforehand, Nintendo of America's legal representatives issued a cease and desist, and the team complied and cancelled the launch. The patch reached the public within hours regardless — a build had already circulated, and once it was out there was no mechanism by which anyone could recall it. The takedown succeeded in stopping the official release and failed at every purpose the official release would have served. Development later resumed and the project was eventually completed and updated. The episode is one of the most-cited examples of the enforcement problem posed by patch-based distribution: the legal instrument is aimed at a website and a release announcement, while the artefact itself is a small file that copies perfectly and travels faster than any notice.