I have recently learned about MissingNo. and I want to see a video of someone encountering it with Pokedex registration. (If you can)
Cry:
MissingNo.'s cry is generally the game's equivalent of a "blank" cry: a Nidoran♂ (base 00)'s cry with a pitch of 0 and no echo. This is because the cries of these Pokémon are undefined in the data structure. A few MissingNo. have different cries (specifically 0x43, 0x45, 0x4F, 0x51, 0x5E, 0x5F, 0x7F, and 0xB5).
MissingNo. (Bulbapedia)
Pokedex Entry:
コメント さくせいちゅう
When translated, this reads "Comment to be written".
MissingNo. Pokedex entries (Bulbapedia)
MissingNo.'s cries may be heard here.