Where do I get a dubious disk?

[TellMeBoutIt716]

I want to evolve Porygon2

[PattySweets4]

I want to evolve Porygon2

north of battle area, i think.

[TellMeBoutIt716]

Thanks a bunch! :D sfgjmxsghnxgh

[rocklee500]

To be more specific, north of battle area on that route, skip the first water then to the next water, surf on that and you will find an item, which is dubious disc.