The Secret Zone is a very plain-looking zone, consisting mostly of empty space and a simple plain of grass with a train track across it. What makes this Zone dangerous are the giant toys that safeguard the areas. Also, the entire dimension appears to be under the Trickster's control.
The Secret Zone was created by the Trickster using the wealth he inherited from his father. From there, he would sent a smart missile to torment Sonic. Meanwhile, Tekno the Canary would discover the Secret Zone's computer system, prompting the Trickster to kidnap Tekno. He then disguised himself as Tekno and lured Sonic into the Secret Zone.
Inside the Secret Zone, a recording of the Trickster told Sonic and "Tekno" to head further into the Zone to face him. As the duo came under attack from several giant toys, Sonic discovered the Trickster's true identity. Admitting defeat, the Trickster released Tekno and began sealing the Secret Zone off from the outside world, giving Sonic and Tekno only a few precious seconds to escape.