GS ball
You catch Cobalion with any Pokeball that is possible to catch it in.
Same way anywhere else, walk around until one attacks, battle it until it's weak, and catch it with some kind of pokeball.
throw a pokeball at it
A lure ball :)
the strongest pokeball is the masterball. the masterball can catch any Pokemon out of the 493. it doesnt matter what kind of Pokemon it is, the masterball can catch any Pokemon.
a quick ball or a master ball
Ash used a lure ball.
any kind, i used a pokeball
I recommend the master ball
you cant you need to use some kind of pokeball
it doesn't matter what kind of pokeball you use it matters how long you take you can catch it with a pokeball as a last resort
Only possible in the Japanese version of Crystal, and maybe the japanese version of Gold/Silver. Kurt gives it to you after some kind of event, and when it is put on the shrine in the Ilex Forest, celebi appears. It is common belief that it is INSIDE the pokeball, but in Crystal, celebi actually floats down from the sky to battle you and doesn't come from the GS ball.