Video: Mod-master MrVicho13 basically took the entire N64 Yoshi Valley course from Mario Kart 8 and dropped it into Grand Theft Auto V, because he could.
Those iconic textures? They were ripped from Mario Kart 8 by a Mr Ray Koopa (probably his real name). MrVicho13 then converted, optimised and tweaked them. Then he wrapped them in a bow and made them available for download for any Grand Theft Auto V PC player to enjoy. By themselves, as multiplayer mods like this are not a thing that can be done.
Good old DayL captured the magic in a YouTube vid of the mod in action.
I would have picked a better course, but then I do not have the skills necessary to put a chunk of one game into a completely different game. MrVicho13 has more maps on the way, so maybe your favourite will show up eventually.