Item from pokemon-kanto by
A mysterious golden-and-silver Poké Ball that neither Professor Oak nor any known analysis can open — delivered by Ash to Professor Ivy for study during the Orange Islands journey.
The GS Ball arrived at Professor Oak's lab from a distant region (implied to be Johto, though no one uses the name yet) with instructions that the Pokémon inside must be examined. Oak's equipment failed to open or scan it. He entrusted Ash with delivering it to Professor Ivy at the specialized Orange Islands research lab. Ivy also failed to open it. The ball was eventually given back to Kurt, a ball-craftsman in an unspecified location. Its occupant remains a mystery.
A Poké Ball-sized sphere, but with a gold upper hemisphere and a silver lower hemisphere separated by a black band — no standard white button, just an engraved 'GS' on the front. Warm in a way that feels unrelated to any Pokémon inside. Will not open by ordinary means.
Also known as: Gold-Silver Ball