Just like the pumpkinhead chao, you can also give a chao an egg shell, and he will put it on his head all you have to do is hacth a new unborn chao, then pick up the top part of the shell and give it to a chao that you want to have it, then he will look at it for a few seconds, and then he will put it in his head. Some chao won't even care about them, they will just through it away. If you don't want the eggshell, you have to get it off the same way you do with the pumpkin !