That isn't possible. You can't just make whatever sprites you want to appear. It has to be programmed into the game, and Missingno is NOT in D/P/Plat.
Actually, the game DOES contain sprites for "missing" data. In Gen III, the name of the Pokémon is "?????" (give or take a few question marks, but I think it's five) and the sprite that appears is a question mark inside a circle. For people that use GameShark and other cheats to do things like walk-through-walls, and who thus manage to encounter a wild Pokémon without having a single Pokémon in their party (because every Pokémon game in existence so far has created various scripts to make sure you can't enter the grass freely before having a starter), that question-mark-in-a-circle with the name "?????" will be the backsprite of your "Pokémon." It has no moves and 0 HP, and as far as I know there's no way to find out what its stats are but they're probably all 0, too.
I haven't seen someone using any similar cheats in D/P/Pl to achieve a similar effect, but presumably, if this "missing" Pokémon sprite and data appears in Gen III, the programmers undoubtedly included similar data in Gen IV. So, the Gen IV "Missingno" probably looks like a question-mark-in-a-circle instead of a Tetris block, and its name probably says "?????" instead of "MISSINGNO," but in terms of what it actually is (not a real Pokémon, but a glitch that the game generates when it's looking for Pokémon data that it can't find), it's essentially the same thing as Missingno.
So, yes, if the way Gen IV is built to handle missing Pokémon data is similar to Gen III, then Missingno IS in D/P/Pl. It's just Missingno by a different appearance and name than the Missingno of R/B/Y.
I don't know how that person was able to glitch up the game to cause it to search for Pokémon data to battle in a place where there are no Pokémon, because typically, if you cause tall grass to sprout in a place like a city where there isn't any wild Pokémon data, nothing would happen when you walked through the grass. But I suppose it is possible.
Here you go, guys.
https://www.pokecommunity.com/posts/4521776/
It is based off of the Decamark sprite :o
Now that is epic. XD I like its moveset. Even if it's not 100% accurate to what the original Missingno was like, I think it's accurate to what Missingno's moveset could be like if it actually were a real Pokémon. Giving it Mold Breaker is also a great idea.
One thing you might want to think about is its TM/HM compatability. According to Bulbapedia: "The TM/HM compatiblilites of the other three forms (i.e., its ghost, Aerodactyl skeleton, and Kabutops skeleton forms) vary based on the last Pokémon species' data the game loaded. In this way, a skilled player can teach their ghost or skeleton form Missingno. any TM or HM in Red and Blue." That'd mess up the nice selection of TMs/HMs you have now, though. Maybe Missingno could be a multiple-Forme Pokémon, and the basic Forme you've got could have those moves, while the other three Formes (Ghost, Skeledactyl, and Skeletops) can each learn different TMs/HMs? So between all the Formes, every TM/HM could be used, even if an individual Forme can't learn them all.
But for the form you've got, though (and particularly since you're making it a Bug-type), the TMs are just fine.
(By the way, you're brilliant for making it a Bug-type because was a
bug in the original game. Nice!)