Nintendo: This “fangame” of yours is copyright infringement and nothing more. Take it down RIGHT NOW or we will sue you for every cent you ever make.
Sega: This Sonic game you made is actually pretty good. How’d you like to make another, as an OFFICIAL Sonic the Hedgehog release? Millions around the world will see your love for our series.
Valve: We like this mod you made. How about you come work for us and release a standalone version as a proper IP? Then neither of us will ever need to make games again, we can be billionaires forever just by making cosmetics.