Give any chao it's OWN broken egg shell after giving the chao a few skelaton dogs and it will put it on. Now reincarnate the chao twice with the shell on the whole time and after the second reincarnation, it will be a full egg chao(I think). A lot of people say you can only do it with some sort of cheat but I'm pretty sure what I just said works. Good luck. I am actually trying it right now.
Chat with our AI personalities
There is no "egg chao" in SAB2, but you can put eggs on an already born chaos. You chao has to be somewhat smart, and you have to be very persistent, but if you keep handing an eggshell or unhatched egg (murder!) to a chao, it will eventually figure out it can put it on it's head, which it will do itself. This effect is permanent and the egg cannot be switched out afterwards, so make sure the egg/eggshell given is a cool one!
You have to buy it
This is how to get a Shadow chao in Sonic Adventure 2 step by step. 1. Hatch a chao egg with Shadow, :Note: the egg shouldn't be from the Black Market at the Kindergarten: 2. Give the chao green chaos drives as Shadow. 3. Pet the chao as Shadow and cuddle with it as Shadow often. 4 Once the speed level is 10 or 15, raise the stamina to level 5, 10, or 15. 5. Wait for the chao to evolve and hopefully, you get a Shadow chao! (I did!)
Your Chao is ready to mate. If another Chao walks close enough to the Chao surrounded by flowers, they will lay a Chao egg together. You can facilitate the process by placing a Chao inside the ring yourself. Note that babies and Chao that have mated recently will not do anything when placed inside the ring of flowers.
Press A on the egg to make it hatch faster!