Yes you can. You just have to find a man in the underground who will trade one to you for the spheres, but make sure you have enough.
you cant't neccissarily battle, but on Pokemon Diamond and Pearl if you and your friend are underground you can break into their base, steal their flag, and run it back to your base and store it on your computer (meeting people underground will get you a chance of catching spiritomb). Its Pokemons version of Capture the Flag.
at the underground mine
its the rarest thing in the underground also it behind the Pokemon statue in Eterna City
You can get a blue, green, red, pale, and prism orb underground.
It is someone who sells traps underground.
If you are referring to secret bases, then a WiFi connection is needed.
You have to meet other people and take their flags in the Underground.
There are secret bases in Pokémon Ruby Sapphire and Emerald. In Diamond Pearl and Platinum, you have underground bases.
You can't buy beds in Pokemon emerald. (one is in your house!!!!!)(and on the S.S.fairy
There are no grass type Pokemon underground!
You can use it anywhere as long as you use it on ground. you can also dig and make secret bases underground!
There are a few Pokemon that live underground such as Diglett and Dugtrio. Also, the move Dig allows Pokemon to burrow underground to attack their opponents.
go underground at heartthrone an Pokemon luage
If oyu have a friend with diamond pearl or platinum.... you'll nedd to go in and out of bases showing each other your trainer cases
No
You can only make normal above ground bases, underground bases are only in diamond and pearl and platinum.
You can't mine underground in either Pokemon Heartgold or Soulsilver, but you can mine underground in Pokemon Diamond, Pearl, Platinum.