ソニックアドベンチャー
Chao have appeared in numerous "Sonic the Hedgehog" video games as digital pets. They made their first appearance in the 1998(JP) / 1999(NTSC/PAL) Dreamcast game "Sonic Adventure". The player can raise them, enter them in races, and export them to "Chao Adventure", a game for the Dreamcast's VMU peripheral. The player can also trade Chao or post their high scores online using the Dreamcast's Internet capabilities. The Chao raising feature was expanded in "Sonic Adventure 2"; Chao may become "Hero Chao", "Dark Chao" or "Neutral Chao" depending on whether the game's "hero" characters (Sonic the Hedgehog, Miles "Tails" Prower, and Knuckles the Echidna) or "dark" characters (Shadow the Hedgehog, Doctor Eggman, and Rouge the Bat) are nicer to them. Chao can enter karate competitions in this game, as well as racing. The Game Boy Advance (GBA) games "Sonic Advance", "Sonic Advance 2", and "Sonic Pinball Party" feature a "Tiny Chao Garden", similar to the Chao Gardens of "Sonic Adventure" and "Sonic Adventure 2" but with minigames in place of racing and karate competitions. Chao can be transferred between "" and "Sonic Adventure DX: Director's Cut"—Nintendo GameCube ports of "Sonic Adventure 2" and "Sonic Adventure"—and the GBA games featuring a Tiny Chao Garden. Unusually, a generic Chao is an unlockable character in the party game "Sonic Shuffle".