Go to the place where Amy was in prison. In the middle
prison cell, there is a multi-colored egg. Hit the 
switch to open the cell and grab the egg. Exit the 
prison room and go to the opposite side of the big room 
you enter. At the extreme opposite side, there is a 
locked door. Spell out 'EGGMAN' with the floor buttons 
to unlock the door. Go in and enter the warp. Hatch the 
egg in the Chao Garden to have a multi-colored Chao!