use your explorer kit
Go underground
You have to go to the underground.
No. The underground is only in Pearl, Diamond and Platinum.
go underground and mine
you have to go underground and dig for him
you need to go underground
In the Pokemon diamond underground.
You cannot go underground as you were able to in Pokemon Diamond and Pearl. You are stuck above ground in Pokemon SoulSilver. You get two regions to go between, though.
Go underground and start diging
You have to be lucky and go underground and dig!
You can find it somewhere or you can go underground and dig it up.
go underground with explorer kit and get a claw fossil