The Carnival Night Zone was a Zone completely constructed on the Floating Island. Supervised by the Marxio Brothers and a handful of Trooper patrols, the Zone was designed to bring Doctor Robotnik money once his Casino Night Zone had been liberated. Somehow, the massive fairground was completely built during Knuckles the Echidna's short absence from the island (or was at least started when the echidna was distracted by Robotnik's treachery). Unfortunately for the location, it was completely smashes off the island when Knuckles revealed who the Marxios were working for.
While it stood tall, the Carnival Night Zone was an impressive feat of engineering and was to be an attraction for the richer members of Zones on the surface of Mobius. Just like a traditional theme park, the Zone was littered with rides, neon lights and fast food stalls. One particular attraction shown was the Hell House Ride, a speedy adrenaline rush that took the rider through dark dungeons filled with ghouls and mud creatures. Knuckles was given a ride on the coaster by the Marxios, although their plan was to kill him by sending him down the incomplete track. Elsewhere, the Zone was protected against intruders by Troopers supposedly bought from Robotnik and Construction Robot workers. In the centre of the area, the Marxios had offices that enabled them to look out on their operation. Knuckles was later given his own room in the block but left it to go and destroy the Launch Base Zone and Death Egg.
Later, as Knuckles ran from the Zone and left it in the hands of the Marxios, the Brothers followed in the Marxio Kart and Chicio Marxio accidentally revealed that they worked for Robotnik. Knuckles began to battle them and, later, a large amount of Badniks sent to delay him. During this time, a transport arrived from the Emerald Hill Zone filled with the Zone's first customers, ready to try out this new Zone. Before they could enter, Knuckles smashed all the Badniks (passed off as another attraction) and punched a fault line near the Zone. Since the Carnival Night Zone was built on the edge of the Zone, Knuckles completely smashed off that portion of the Floating Island, removing Carnival Night from the island. A few seconds later, the Zone fell to Mobius, slightly cushioned by remaining Master Emerald power. The crash-landing of the ruined Zone was a shock to one Emerald Hill boy who had just before wished that the Zone was closer.
- The Zone was originally found in Sonic the Hedgehog 3, but Knuckles did not seem to mind the lively attraction being on the island at this point.
- Despite the name, the Zone is only ever seen during the day.