Originally Posted by Thunderbird
Yes, the Missingno cheat is available in Red/Green/Blue, but is taken out since Yellow.
This is blatantly false.
Missingno can be encountered using the Mew Trick in Yellow. Note that the missingno yellow is a bit trickier than the r/b one... seeing it will freeze the game about 4 times out of 5 or so, and it can't be trained like the r/b missingno (although it can be rare candied; the exp required for it to get to the next level is simply insane), I'm pretty sure it's otherwise safe (again, pretty sure; they may well have been responsible for the mysterious loss of data I experienced one day).
(Note: The claim on the picture that yellow missingo does not duplicate items is false.)