The Invisible Chao is the Chao that is completely invisible! There are 2 ways to get this Chao. You can mate a Shiny Grey Chao (costs 10,000 rings in Black Market) with a Jewel Chao. Or, you can mate a Shiny Yellow Chao (costs 5,000 rings in Black Market) with a Jewel Chao. Now, the Chao won't be completely, completely invisible. Sega created it to be able to see its ball, spikeball, halo (etc.) and its wings (maybe). So, when done, you have an invisible Chao!