This Pokemon is actually referred to as -----.
>----- is a Normal-type glitch Pokémon in Diamond, Pearl, and Platinum. It is often referred to as DPBox due to its appearance and the games it was discovered in. It is also often referred to as invisible Shiny Bulbasaur when appearing on the opponent's side due to having the cry of Bulbasaur, always being Shiny, and seemingly having no sprite.
It's a very interesting glitch as the game treats it as if it's not existent. (Games can be jerks to glitches sometimes...)
So is this glitch safe? It is mostly safe; it will not corrupt game data and you can use the glitch in battle, although it is flat out useless. However, one extremely creepy side effect (or at least it sounds creepy as Bulbapedia uses vocabulary such as "loom.") could corrupt or delete one of your Pokemon:
>If ----- is the last Pokémon in the party, and the player tries to add a Pokémon to said party, the Pokémon from the Box will have a party sprite with a different color palette. Then when the Box is exited, the Pokémon will loom over the Box and disappear from the party.
So watch out for that...
Hope I helped!
Here's my Source if you want to learn more about -----.