Catching it = not good. Using it to get infinite Rare Candies, master balls and TMs = good. Only, don't use it to multiply fossils. Yeah, you can get 100+ Aerodactyl but then what? Is it worth the time? Not only that but you can only deposit 1 key item into the computer at once.
Missingno Cheat in all its glory: Talk to the man in Viridian and let him teach you to catch pokemon. Fly to Cinnabar Island. Surf along the edge, half on land and half in water. You'll find Missingno or M in no time. Also, you may find pokemon in the last area you visited, allowing you to use Master Balls on Safari Zone pokemon. Sometimes, level 126 Starmie or Golduck appear as well. Leveling them up takes them down to 100. Don't catch Missingno. The stuff's all true. I don't remember exactly what happens if you do, but I remember catching it and having to start a new game. My Hall of Fame doesn't work anymore... I don't know if that's just because I performed the glitch or if it's because I caught it on a previous file.
There is a fun trick with MissingNo. Put a candy bar as your sixth item in your bag. See MN, then RUN. You shall see that you have way more candy bars then you did last time! Time to add EXP!! And wityh this trick, I hear that you can make level 100+ pokemon.
Anyway, if you DO catch missingno, it will turn into a kangaskan.
I have this weird glitch. (All true, really) I was playing my gold version, and all of a sudden, in the multiplayer lounge in the health places, the game froze. When I restarted, the Ho-HO on the title screen went from a shadow to it's color! (Before, it was dark, you couldn't see what it was, then it was visible!) When I went back to the MP, I had ro fight a guy with a butterfree that had it's health go accross the screen.
The title screen glitch happened to me after the game froze and I reset. It freezes a lot...
I think that's Missingno. Wow. This reminds me of all the hundreds of Bogus pokemon cheats that were all over the internet at the height of it's popularity.
Some bogus cheats include getting Mew instead of Mewtwo at the end for nicknaming your starter Mew. One even said you could get Yoshi instead of Mewtwo. If you think that's stupid... I even read one to replace Mewtwo with SPONGEBOB. Not only is that copyright-illogical, but Spongebob was invented in 1999, a year or so after pokemon was made.