You find the Dubius Disc in the P2-Labratory in pokemon white. Hope that helped :)
A dubious disc is a hold item for Porygon2. If you trade a Porygon2 that's holding a dubious disc, it will evolve into Porygon-Z.
The Pokemon that uses the Dubious disk is Porygon2 to evolve him into a porygon-Z
you can't. dubious disc is to evolve porygon 2 into porygon z, porygon z is a sinnoh Pokemon and leaf green only goes up to hoeen
If you give the item to a Pokemon to hold, and then trade it, then your Pokemon will evolve. I am not sure if this only applies to Porygon or if it will work for any Pokemon but I hoped this helped
Jirachi
You find the Dubius Disc in the P2-Labratory in pokemon white. Hope that helped :)
On the bonus disc of Pokemon colosseum you can get a jirachi legitally and that's the only thing that's on that disc other than a preview of colosseum and the movie jirachi wish maker.
Only you can get it from the preordered special disc of Pokemon colosseum.
non
pokemon/ japan 1998
disc
go to survival area there will be a poké ball if you seek it then its dubious disc
A dubious disc is a hold item for Porygon2. If you trade a Porygon2 that's holding a dubious disc, it will evolve into Porygon-Z.
Coloseum bonus disc for game cube.
You can do it by using a cheat disc for the gba.
It evolves porygon2 (trade)