The Chaos Chao first appeared as Chaos in the events of Mission: Chao Retry. He is a baby chao that is very sweet, kind, shy, curious, and kinda a cry baby. He looks up to Nox mostly, but Yuu, also. Whenever one of the Heroes wheres the gold ball, the Chaos Chao will turn into the water monster, Chaos. The Chaos Chao is made of gooey water.
When Rascal placed the ball among his head, Chaos appeared in the Lobby. The chao fought him and he "died", turning into an egg. This hatched into the Chaos Chao, which looked up to and followed Nox.
So far, the only times the Chaos Chao really effects the plot is when he turns into Chaos. Chaos is about the height of the waterfall in Chao Gardens and about the width of the lake in Chao Gardens. It has a dark sphere in its center, marking its weak point. It can repair itself and grow tentacles, which it flings at people. Chaos can also take on other forms of liquid, too. Such as turning into gooey blood and turning red. Chaos can also freeze for a while.
The Chaos Chao now has a metal coating. It is unknown if he's completely metal or not. This occured when Chaos Transformed during The Battle of Neutral Chao.
Chaos has no alignment, even if it feels it may be good. Chaos can attack anyone, but does have free will in it. Chaos doesn't take orders, either, and will fight independently.
When the ball is removed, Chaos turns back to the Chaos Chao. Apparently, the Chaos Chao growls at the sight of the ball, showing that the Chaos knows something about it.
Game Breaker- The most intricate of plans fall apart when faced with an invincible water monster.
The Blob- Made of almost-water.
What The Hell Hero- Stop genocide? Nah. HELP genocide? Now THAT'S doing some good!
Chaotic Good- Screw the rules he's a benevolent deity.
WaterWorks- Warning: can cause floods. Weird, considering he's made of water.
Combat Tentacles- Uses these to drown people in itself.
Boring Invincible Hero- Is literally invincible.