Oh, I know 'M' is different as similar as it looks. And MissingNO. in fact DOES do a garbage save. Fight one in Pokemon Stadium on the GB Tower and watch the "Saving..." appear when he comes up.
That's through Stadium, not on RBY itself. It doesn't save RBY whenever you encounter them.
The GlitchDex and TRsRockin are very good. Probably the best place to get glitch information on the net! :p
In that case, lemme quote TRsRockin.
"MissingNo does not make your game save when you encounter it."
- From
this page
Also, lemme quote what they say about 'M:
"'M seems to cause much more damage to your records and Hall of Fame than MissingNo. Even encountering one will make your game save (you can see this happening while playing on Stadium 1 or 2)."
- From
here
Also, this is from the Glitch Dex I've found. (I realize it's not
the Glitch Dex, but it's close enough.)
"However, your game automatically saves when you encounter 'M, unlike MissingNo,"
-
Here
So, I'm thinking you might've confused 'M for Missingno here unless they did.
It's been said; MissingNO. is placeholder data. There is a question that's been nagging me, though. Why the mess of pixels rather than some sort of proper sprite?
Because the mess of pixels is a placeholder as well. Occasionally, you get actual sprites (e.g. Ghost Missingno), but more commonly, you'll get the garbage that's left in the slots that were never meant to be called up in a Pokemon encounter.
Are bird-types weak to the same things as flying?
I've tested this, and apparently not. On the other hand, I had also created my test by Sharking a Missingno in place of Bulbasaur at the start of the game, so that might have something to do with it.
Also, thanks to Monzae, but you'll probably find better information in the Missingno sticky or on other websites. I just gave you what I could remember and a sort of messy explanation about it. ^_^;