How do you make or get a shadow chao sonic adventure 2 battle

You use shadow during the whole time, so, you pet your chao a lot of times with shadow so it will turn black. Once it turns black you will have to give it green class animals or green chaos drives , but i would prefer green chaos drives. you make the run at 20-25, and stamina 15-25. Then you sill slowly see horns coming out of the back of the head. then one day it will go into a cocoon and there will be horns ,but the out line will be green. so you have to give it more green chaos drives and more stamina. Then the out line will turn red.