I stumbled upon the topic of interactive demo discs for the gamecube systems. What are these discs uses?
They had various demos for stores to let people try out game demos before there was an era where you could simply download a demo online for nintendo products. There also were some events and patches on these demos such as berry fix zigzagoon, a shiny zigzagoon event that also happened to fix the berry glitch in ruby and sapphire. Another event for another series exclusive to japan was one where character chaos: Knuckles, Tails, and Amy were given out to people. These chaos could be brought to Sonic adventure 2 and kept there. That was the only way to obtain these chaos outside of tails also being available from phastasy star online.