Hoping to convert the discovered Hidden City of the Ancients into "Robotnik Land", Dr. Eggman freed the water beast Chaos from the Black Emerald and attempted to use it to destroy the city. Although Chaos was first thought defeated, it managed to transform into Perfect Chaos and severely damage the city. By this point however, Chaos no longer wished to work for Eggman, and destroyed his second Egg Carrier. After this failure, Eggman unleashed Silver Sonic II to capture the city, but this robot was subsequently defeated as well and reprogrammed to defend the city from Eggman. (StH: #79, #80, #83, #84, #85, SSS: #13)