Under very special circumstances, it is possible for a Chao to evolve into a special type called a Chaos Chao. Chaos Chao are named after the beast Chaos, from Sonic Adventure.
Chaos Chao are special in that they are immortal; they will never die nor reincarnate, no matter what. Once your Chao succeeds in transforming into the legendary Chaos Chao, it will stay in that form forever. You should therefore choose wisely before pursuing this transformation; in particular, you will not be able to raise your Chao's stat grades after it transforms.
Please note, the following will tell you the correct way to attain a Chaos Chao figured out within the Chao Island forums. For years, Chao raisers have not been aware of this correct method to evolve a Chaos Chao properly!
There are four general requirements that your Chao must satisfy in order to transform into a Chaos Chao. There is also a fifth alignment requirement, if you want to get a specific kind of Chaos Chao.
- Your Chao must have reincarnated at least twice. This means it must be on its third life or more.
- Your Chao must have over 50 happiness. Happiness is a hidden value which runs from -100 to 100, and it is increased by caring for your Chao well. Your Chao must have had over 30 happiness to reincarnate, so you shouldn't have much trouble hitting this requirement.
- You must give your Chao at least one of every animal in its current life. Contrary to popular belief, you can give your Chao more than one of each animal. In other words, your Chao must have learnt every animal behaviour. The animals that you have given to your Chao in its previous lives will have no effect on this.
- Your Chao must be balanced, so that it would otherwise evolve into a Normal type. Your Chao must not be set to evolve into a Swim, Fly, Run, or Power type. This is how the false belief that you must give only one of each animal came about. Giving an equal amount of each animal is the easiest way to ensure this requirement, though.
- If you want a Neutral Chaos Chao, otherwise known as the Light Chao, then your Chao must be of the Neutral alignment. Give it a balance of Hero Fruit and Dark Fruit, or none at all.
- If you want a Hero Chaos Chao, otherwise known as the Angel Chao, then your Chao must be of the Hero alignment. Make sure you feed your Chao enough Hero Fruit.
- If you want a Dark Chaos Chao, otherwise known as the Devil Chao, then your Chao must be of the Dark alignment. Make sure you feed your Chao enough Dark Fruit.