That item doesn't exist in leafgreen.
trade porygon2 with the item dubious disk to evolve the the Pokemon porygon two then get it back
You can give the Upgrade to Porygon and then trade it to a friend to make Porygon evolve into Porygon2, in order to evolve Porygon2 then give a Dubious Disc to Porygon2 and then trade it to someone and it'll evolve into a Porygon-Z.
The dubious disc is used to evolve PORYGON2 into PORYGON-Z a new version exclusive to Diamond/Pearl/Platinum. To evolve PORYGON2 make it hold the disc and trade to a friend then get them to trade PORYGON-Z back.
Talk to Professor Oak in the Southwest of Eterna City after beating the Elite Four. He will give you the Up-Grade.Then, let PORYGON hold the Up-Grade and trade it to another person. It will evolve after trading. After this, trade it back to your own game.
You cannot catch Porygon2 in the wild, you will have to trade a Porygon holding an Up-grade to evolve it into Porygon2.
You evolve Porygon2 by giving it the Dubious Disc and then trading it to another player's game.
The Pokemon that uses the Dubious disk is Porygon2 to evolve him into a porygon-Z
you cannot evolve a porygon2 in leafgreen
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.
You have to trade with it holding the dubious disk. This can be done when porygon2 is at any level.
porygon2. give it to him trade and it will evolve.
trade porygon2 with the item dubious disk to evolve the the Pokemon porygon two then get it back
It can be used to evolve a porygon2 when equipped and traded
give it a dubious disk and trade it
Porygon2 will evolve into Porygon-Z once you trade it to another player while it's holdig a Dubious Disc.
Porygon2 doesn't evolve you need to trade it holding a dubious disk
If you make the Pokemon Porygon2 hold it then you trade Porygon2 while it's still holding it, it will evolve into Porygon-Z