In order to acquire the immortal Chaos Chao transform a Chao at least two times. This means that your Chao must create a tear-shaped cocoon around it self twice. After this has been accomplished, give your Chao (hero, neutral, or dark) one of each animal. On the third transformation, your Chao will become a Chaos Chao. Note: This will not work if your Chao dislikes you.

Raise your Chao's stamina to about level 7 to 15 to send him through his first metamorphosis. Leave the Gamecube on overnight while you are in the garden. It is recommended that the Chao be alone in the garden. Then, check your game and he should be a baby which is good. After that, repeat the first metamorphosis process. Once evolved again, leave it on overnight once more. Now that your Chao is a baby again (for the third time), give it one of every animal. Finally give it a Hero Fruit for Hero Chaos Chao, a Dark Fruit for Dark Chaos Chao, and a Chao Fruit for a Light Chaos Chao. Wait for awhile for your well earned Chaos Chao.

Start abusing your Chao with the type of storyline you do not want your Chao to grow up to be. It will transform eventually. Repeat this until it has transformed three times. As you begin the rest of the game, give your Chao each small animal you find and that one Chao. It will turn into a Chaos Chao.

Get a fresh egg (white and blue only). Feed it only Chao Fruits and train it nicely with both sides, Hero and Dark, until it evolves once. It will create a cocoon in the shape of the Chao's head. If done correctly, it will be a baby blue Chao again. Repeat the last step until it evolves for the second time. After it has evolved twice (it should still be blue), give it one of every animal. Then, give it a Chao Fruit for a Neutral Chaos Chao, a Dark Fruit for an Evil Chaos Chao, or a Hero Fruit for an Angel Chaos Chao.