Chao

Chao (チャオ) is a mystical species in the world of Sonic the Hedgehog that is usually found in magical areas called Chao Gardens. Their role in the games are to be raised by the player in mini-games, similar to many virtual pets. Chao are somewhat complex: they respond to stimuli, have moods, require food and can be loving or fearful. The word Chao is a pun on Chaos, a word commonly used in the Sonic series and which is why the word remains unchanged when plural. The Chao are the good friends of Chaos and Tikal.

During the Archie Comics crossover Worlds Collide, a pair of Chao, including one who had taken on the characteristics of a Met, were in the Skull Egg Zone to provide footage of Mega Man, Proto Man, Sonic and Tails as they battled Copy Robot and The Genesis Unit. (Sonic Universe #52)

Cheese
Cream the Rabbit has a Chao named Cheese, the two being seen together most of the time. Cheese was part of Team Freedom during the time that New Mobotropolis was under the attack of the Tails Doll. (Sonic the Hedgehog #247/FCBD 2013) When the world was changed by the Super Genesis Wave, Cheese became a member of the Freedom Fighters alongside Cream.

Omochao
Omochao is a supporting character from the series, a robot shaped like a Chao that flies with the propeller on its head and has extensive knowledge. In the world after the Super Genesis Wave, Omochao is a robot that gives support to the Freedom Fighters, being mainly used as a communicator. He appears in Worlds Unite.

Other media
Chao appears in Super Smash Bros. for Nintendo 3DS / Wii U as a trophy.