You are trying to rencarnate your chao in SAB 2 but you dont know how yo prevent them from disapearing you dont want a chaos chao you just want it to rencarnate with out dying no animals nochao fruit

This is because of lack of proper care, such as petting it and feed it fruit. If you have saved it just before the Chao has tried to die, you will be able to, if fast enough, reach the Chao before it goes into the grey cocoon. Pick it up, then feed it multiple fruits in a row. Then, Pet it for a while. If you did it well enough, it should go into a pink cocoon and reincarnate.