Flickies' Island (interchangeably referred to as Flicky Island within the game text) is the setting for Sonic 3D. The island is presumably not too far removed from South Island, as Sonic occasionally stops by on his travels to check up on his friends, the Flickies: brightly coloured birds which have been seen all over Sonic's world since the very first game.
However, these Flickies are special. The birds are native to another dimension, and travel to and fro between the worlds by means of giant rings. While such metaphysical chicanery doesn't faze Sonic, the megalomaniacal Doctor Ivo Robotnik becomes very interested in the Flickies' powers after learning about the Island. Eggman resolves to robotize the interdimensional creatures, and harness their strange abilities to further his search for the Chaos Emeralds - thereby setting in motion the events of Sonic 3D.
As with South Island, Flickies' Island manages to pack an impressive array of facilities and climates inside its coastline. The only game which has visited Flickies' Island is Sonic 3D, and all its levels are sited there:
In the Fleetway Sonic the Comic series, Robotnik was ousted from power as the dictator of Mobius in issue #100. The Doctor fled to Flickies' Island, where he constructed a secret laboratory and developed a new line of deadlier badniks, intending to regain control of the planet.
It was later revealed that Flickies' Island (specifically Rusty Ruin Zone) had once been inhabited by the Drakon Empire - also responsible for the giant rings present on the island. After making a deal with the interdimensional Drakon, Robotnik ran his operations from Flickies' Island and attacked Mobius repeatedly with his new model badniks. His base was destroyed in issue #132.
In the Archie continuity, and a little closer to the storyline of Sonic 3D, Sonic responsed to a distress call from Flickies' Island, arriving to find that Eggman had captured the island, roboticized the Flickies, and was in the midst of a search for the Chaos Emeralds. Sonic soon found out that the robot Flickies were vulnerable to seawater, and reverted to their flesh and blood forms on contact. Sonic raced through the Zones and defeated Eggman, who fled.
|Sonic 3D: Flickies' Island|
|Locations in the Sonic the Hedgehog Game Series|
|Islands||Christmas Island | South Island | West Side Island | Angel Island | Cocoa Island | Flickies' Island | Prison Island | Onyx Island | Southern Island|
|Landmarks||Never Lake | Mount Mobius | Emerald Shrine | Tails' Workshop | Babylon Garden | Gaia Gate|
|Regions / Nations||Eggman Empire | Station Square | Mystic Ruins | United Federation | Central City | Soleanna | Monopole|
|Vessels||Death Egg | Death Egg II | Egg Carrier | Space Colony ARK | Eggman Fleet|
|Planets / Planetoids||Mobius | Little Planet | Black Comet | Interstellar Amusement Park | Lost Hex|
|Dimensions||Special Stage | Maginaryworld | Sol Dimension | Arabian Nights | Twilight Cage | Grand Kingdom | White Space|