Chao (Sonic the Hedgehog)

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,[11] 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.[12] The Chao raising feature was expanded in Sonic Adventure 2; Chao may become "Hero Chao" or "Dark 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.[2] 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.[13][14][15] Chao can be transferred between Sonic Adventure 2 Battle 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.[16][17] Unusually, a generic Chao is an unlockable character in the party game Sonic Shuffle.[18]

Chao have also appeared in the series as minor characters and gameplay elements. Two Chao—one Normal and one Dark—who drive Chao-styled mechas are playable characters in the two-player battle mode of Sonic Adventure 2: Battle.[19][20] On the Sonic the Hedgehog-styled pinball board in Sonic Pinball Party, one of the player's objectives is to hatch several Chao eggs.[15] Each world in the 2004 GBA game Sonic Advance 3 features Chao-inspired minigames to earn extra lives for the player, and a sidequest that involves finding Chao to obtain Chaos Emeralds.[21] 2007's PlayStation Portable installment Sonic Rivals 2 hides Chao throughout levels to be found in a free play mode.[22] In the 2008 Nintendo DS role-playing game Sonic Chronicles: The Dark Brotherhood, Chao eggs are hidden throughout the in-game universe for the player to find and hatch.[23] The resulting infant Chao can be equipped to characters. This affects the characters' performance in battle; for example, one kind will increase the character's hit points. The game features a multiplayer mode in which Chao can be traded between players who each have a copy of the game.[24] Chao take the form of an item in the "Panel Flip" party game of the 2009 Wii and DS game Mario & Sonic at the Olympic Winter Games. Each player's object is to claim as many panels as possible in a six-by-six grid; finding a Chao upon flipping a panel claims all panels in a given row or column for the player.[25] One mission in Sonic Generations (2011) involves racing against Cream the Rabbit to collect lost Chao in a city location.[26]

Cream, a prominent character in the series, has a Chao named Cheese as a partner. In a move to keep her image safe, she often uses him to attack enemies instead of doing so herself.[27] Other notable Chao include Chaos, guardian of the Chao, who serves as an antagonist in Sonic Adventure;[12] Omochao, a robotic Chao who appears in several games as a means of player tutorial;[28] and Chocola, Cheese's twin whom Cream, Amy Rose, and Big the Cat search for over the course of Sonic Heroes.[29]

Chao have also made appearances in video games outside the Sonic the Hedgehog series. In the 2004 PlayStation 2 game Sega Superstars; the player uses points earned during the game to please a pet Chao.[30] Marking the introduction of the character Sonic the Hedgehog to the 2008 Wii game Super Smash Bros. Brawl, Chao and other characters from the Sonic the Hedgehog series appear as collectible trophies[5] and stickers.[31]

They also appear as trophies in Super Smash Bros. for 3DS and Wii U and as spirits in Super Smash Bros. Ultimate.

Chao were recurring characters in the Sonic X anime that ran from 2003 to 2006. In the episode "Little Chao Lost", Cheese becomes lost while swimming in a stream. The main characters find him at the stream's end, in a Chao colony, where Doctor Eggman shows up to steal a supposed Chaos Emerald from them until he is defeated.[32] Later on, in "Flood Fight", a colony of Chao appears after a battle with Chaos; they turn out to be Chaos' old friends and embrace it as it leaves with Tikal the Echidna to return to the past.[33]

Chao have also made occasional appearances in Archie Comics' Sonic the Hedgehog comic book series. They debuted in an Sonic Adventure-based story arc, where they work together with Tikal to defeat Chaos.[34] At one point, Sonic, Tails, and Knuckles find a Chao garden and one Chao followed Sonic home, and after spending time around his Roboticized father came to resemble Omochao.[35] However, Eggman destroys the garden, and the Chao migrate to a lake.[36] Much later, Cream and her mother Vanilla protect a frightened but incompetent group of Chao from Eggman's assistant, Snively. Cream's friend Amy Rose realizes they are the same group from the lake and, to Cream's delight, suggests that the lake can be converted to a Chao garden.[37] Following the comic reboot, Cheese continued to accompany Cream while Chocola was revealed to live with her mother Vanilla and Gemerl (from Sonic Advance 3). The heroes would also discover a Chao Garden hidden in an undersea cavern whose inhabitants included an ancient Chao named Aquarius and a guard dog-like Chao named Crusher.

Chao were prominently featured in the official web short "Chao in Space". The premise references billboard props in the Sonic Adventure series, which appeared to advertise a fictional movie of the same name. The short alternates between a Chao's dream in which it is piloting a space ship, and between Sonic trying to keep the aforementioned Chao under control as it sleepwalks.[38] The short was accompanied by the release of some related merchandise through the official Sega Shop website.[39]

In IDW Publishing's Sonic the Hedgehog comic book series, Chao have a prominent role in the "Chao Races & Badnik Bases" arc, in which Rouge competes in Chao races with Cream's Chao, Cheese, to defeat champion Chao racer Clutch and obtain parts for the nearly-destroyed E-123 Omega from him.[40]