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 can be bought in Pokemon X and Y and can be sold for a price of 
1050.
Description
- 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.
Locations
- DPPt: Route 225, Team Galactic's HQ (Pokémon Platinum only)
- HGSS: Route 42
- BW: Route 13, P2 Laboratory (Event-exclusive storyline)
- ORAS: Can be bought in a shop at the Battle Resort.