Diamond/Pearl Glitch: Invisible Shiny Bulbasaur
Invisible shiny Bulbasaur (so named because it has no sprite, sparkles when it appears like a shiny Pokémon, and uses Bulbasaur's cry) is a glitch Pokémon found in Sinnoh's Oreburgh Mine.
When it appears, it is level 0 and has zero HP, much like ?????????? in Generation III. If it is attacked, the game will assume there is no target and end the battle immediately.