Go to the right of socelean town you will see a cave
I dont know what happen in diamond, but in platinum you can catch ! and ? unowns.
yes, you can get a uknown. you can get it in solaceon town in the ruins. You can grt all of them.
to do this you have to catch all of the unknown and talk to the wall and he will appear randomly on the game. Hope i helped.
Pearl/Diamond-Lv.30Platinum- unknown
Yes you can at the Solaceon Ruins. Battle/Catch 99 Unknown and the 100th Pokemon you see will be Celebi.
Go to scolaceon town's ruins and run around and poof!!! You have unknown. But, bring dusk balls to catch them. Also when you catch all of the unknowns (A to Z) Go to maniac cave go all the way down maniac says he dug into this weird place and go in and you can battle ! and ? unknown.
you can't catch him in platinum but in soulsilver or heartgold you can catch him then trade it to platinum.
After you catch ALL the other unknown, go to the ruin manic cave. go all the way down it, and in the room at the end of the tunnel, you can catch the exclamation and question mark unknown!
first catch all the unknown. then go to the ruin maniac guy . he will be done the tunnel go in it and at the end of it you should find them.
you have to catch a through z in unknown then go to ruin maniac from the bottom of veilstone city (cave on brown ground) he will let you through to catch ? and !
how do you catch a mewtwo on Pokemon platinum
Unknown are in Pokemon games for events like in Pokemon diamond, Peral and Platinum when you have to catch all the unknown and show them to the tunnel maniac under hearthome city i think and then you get a prize!