Originally Posted by Sith_Lord_Darth_Krushya
I don't understand why people like missingno. It's not even a real Pokemon. It's glitched data and it can harm your game save. I encountered it a couple of times when I first started playing Red and Blue but never caught it. Then I heard that it was a potentially harmful glitch and so I was glad I never did catch it.
We like missingno and other glitches because it provides a whole new facet to the game. The value lies in exploring regions of the game even the designers haven't charted, in my opinion. :)
And no, missingno won't damage your save file (although Yellow Missingno will frequently freeze your game upon encounter). 'M, a similar glitch, will cause problems if you put it in your PC, and both will corrupt your Hall of Fame data and may cause minor graphical disruptions, but neither are known to erase save files or cause permanent damage. (Although some sources suggest .4, a different glitch, may delete game data. I've heard conflicting stories on that one.)
(Ignore anything Nintendo says about Missingno and any glitches. Nintendo understandably has a strong anti-glitch bias.)