MissingNo. - The setup

Talk to the old man in Viridian City and let him show you how to catch Pokemon, then go to Cinnabar Island and surf along the east coast. Do not leave Cinnabar Island or you'll have to start over. Depending on your name in game, you should encounter MissingNo., â–„'Mâ–“, a normal Pokemon at an extremely high level, or a "Wild Trainer". My name in this playthrough is w x y (threespaces-w-space-x-space-y), which allows me to encounter Kabutops Fossil MissingNo, a Venonat and a Weepinbell (it was supposed to allow me to see all MissingNo. variants except the normal one, but I guess that doesn't work).