The Heavy Ball was introduced in Generation 2 and has a higher catch rate the heavier the wild Pokemon is. In Gold/Silver/Crystal, Heavy Balls are created by Kurt in Azalea Town using Black Apricorns.

However, in Pokemon Crystal, gamers would need to have the rare item, the GS Ball, to trigger an in-game event that would lead to the capture of Celebi. This event to receive the GS Ball was only ...