"pokemon diamond"

after looking at all of the new pokemon and realising how strange it will be to play with none of the persistently appearing pokes like zubat or tentacool, i remembered a game i played around 10 years ago on an emulator. it was really foreign (in every sense of the word) and clearly isn't a part of the pokemon series. i just looked and i still have it, but i'm wondering anyone knows what the heck this really is. like i said, it's called pokemon diamond and has a picture of lapras at the start and then... goes downhill from there. here's an image i just took



anyone know anything about this?