Chao

A Chao (chow", singular and plural form Chao) is an artificially intelligent, virtually generated lifeform from the Sonic the Hedgehog video game series. Their role in the games is to be raised by the player in mini-games, similar to Tamagotchi. Chao are somewhat complex, responding to stimuli; they have moods, they require food, and they can be loving or fearful. The word Chao is a pun on Chaos, a word commonly used in the Sonic series.

Making their first appearance in Sonic Adventure for the Dreamcast (both in the plot and in a Chao-raising aspect of the game), later in Sonic Adventure 2, and further enhanced in Sonic Adventure 2: Battle and Sonic Advance, Chao have recently come to be a large part of the Sonic the Hedgehog franchise. The A-life system used for the Chao was introduced in Nights into Dreams... as the Artificial Intelligence in the Nightopians.

Chao-raising and the main Sonic games tie together in a number of ways: items which you encounter in the main game can be used to raise your Chao, collected Rings can be used to buy things for them, and several unlockable features are related to Chao.

During raising, Chao have statistics: Swimming, Flying, Running, Power, and Stamina, as well as luck and intelligence, which aren't quite as obvious. These statistics can be raised through proper Chao raising, and will enable a Chao to do better in their competitions: racing and karate.