Chao (Sonic the Hedgehog)

Chao
Sonic the Hedgehog character
A screenshot from Sonic Adventure 2: Battle showing three Chao: "Dark", "Neutral", and "Hero" (from left to right).
First game	Sonic Adventure (1998)

Chao (/ˈtʃaʊ/; Japanese: チャオ) are fictional life forms in the Sonic the Hedgehog video game series published by Sega. They are small, childlike creatures that go through a complex life cycle and exist in several visual forms depending on how they are raised. Developer Sonic Team incorporated Chao into the games to encourage players to explore levels and support the good–evil dichotomy of Sonic Adventure 2.

Chao have appeared in many games in the series, beginning with Sonic Adventure in 1998. They usually take the form of digital pets, but have also played parts in the story and figured into other gameplay elements. Most notably, the character Cream the Rabbit has a Chao named Cheese, whom she uses to attack enemies. They have also appeared in games outside the series, the Sonic the Hedgehog comics, and the Sonic X anime, as well as being featured in promotions and merchandise. Critics have given mixed opinions on Chao and their integration into Sonic gameplay, generally praising their worth as a diversion but criticizing Chao minigames' low interactivity.

Sonic Team's Takashi Iizuka stated in an interview with video game publication 1UP.com that Chao were incorporated into Sonic Adventure "so that new players would be forced to go out, explore the action sections, and find Flickies and things." Chao were designed as a "relative neutral entity" in this game. However, to remain consistent with the good–evil dichotomy of Sonic Adventure 2, they were designed so that the player could raise them as "Hero Chao" or "Dark Chao". Chao were given the ability to socialize and interact in Sonic Adventure 2 in order to make the game unique, and to more resemble "a real artificial life form."