'M' is just another version of Missingno.
There is no M there is a N but there is a N.
The answer, is Mew, M is the short for Mew
I`m sorry but you cannot get it in pokemon naranja
the unknown M is in the rixy chamber
Sort of like misigno
Aids
the shiny Pokemon code for AR 1b3jt59xr438
cubone have it
fcff33345456781acd
You are given a TM when you will need it.
You can find the M form of Unown in the Solaceon Ruins of Pokemon Platinum. This form of Unown appears in the dead-end rooms of the Ruins.
Pokemon party!P-O-K-E-M-O-N