| ||Can't be bought|
| ||No type|
The Dubious Disc (あやしいパッチ Suspicious Patch) is an evolution item that allows you to evolve specific Pokémon and was introduced in Generation IV. The Dubious Disc item is used to evolve Porygon2 into Porygon-Z while being traded. However Porygon2 must hold this item in order to evolve. It cannot be bought in any way but can be sold for a price of 1050.
- DPPt/HGSS - A transparent device overflowing with dubious data. Its producer is unknown.
- BW - A transparent device overflowing with dubious data. Its producer is unknown.