- You may be looking for the Miracle Planet from Sonic the Comic.
The Little Planet in the ending of Sonic CD.
in other media
Varies (Appears over Never Lake one month out of every year)
Stuck inside the powereless Death Egg Mark II in space.
The Little Planet (リトルプラネット Ritorupuranetto?), also known as the Miracle Planet (奇跡の星 Kiseki no hoshi?), is a satellite in the Sonic the Hedgehog series, and the main setting of Sonic the Hedgehog CD.
According to legend, the Little Planet appears over Never Lake one month out of every year, and vanishes completely for the remaining eleven months. It is unclear where precisely it vanishes to, although its appearance above Earth would suggest that it is in geostationary orbit.
Also notable is that the Little Planet is home of the so-called Time Stones. They cause various temporal anomalies on the Little Planet, and may be largely responsible for the planet's annual disappearance. Through the use of Time Warp Plates (similar in design to Star Posts), it is possible to travel to three distinct time periods - the present, the distant past, and an unspecified point in the future - although in the adaptation of Sonic CD in Sonic the Comic, this sort of time travel was only possible if in possession of one of the Time Stones itself.
Sonic the Hedgehog CD
During Sonic the Hedgehog CD, Doctor Robotnik attempts to conquer Little Planet, utilizing Metal Sonic as his primary minion. In fact, it is one occasion when Robotnik actually succeeds in creating his "Eggmanland utopia", by using Little Planet's bizarre chronology to invade the planet in the Past so that it would be under his control in the Future. He connects Little Planet to a rock formation carved with his face by means of a massive chain.
The grim future of Little Planet ruled by Robotnik is bleak and mostly in ruins, though, with the Badniks around the levels broken down and deteriorating. Through destroying Robotnik's machines in the past and/or collecting the Time Stones (finding all 7 of which automatically ensures a good future for all rounds), it is possible to liberate the planet from Robotnik, and institute a truly utopian "Good Future".
At the conclusion of the game, Sonic rescues Amy Rose (who had been kidnapped whilst following Sonic on Little Planet) and lands back on Earth as Robotnik's fortress falls apart around him. As he does so, the chain linking the Little Planet to Sonic's world shatters, allowing Little Planet to rise away from the planet's surface. In the bad ending, it will disappear and later reappear still covered in Eggman's machinery. In the good ending, however, it will be a grassy utopia. It will disappear in a flash resembling Sonic's head, and sparkles will drop down onto the surface of Sonic's world, causing flowers to immediately grow (these flowers resemble the ones created when Sonic destroys a badnik in the game). In the good ending, the Little Planet does not reappear.
Sonic the Hedgehog 4
The Little Planet reappears in Sonic the Hedgehog 4, where it has been mechanized by Doctor Eggman to make a new version of the Death Egg, which can be seen in Act 3 and the boss act of Sylvania Castle Zone and boss act of White Park Zone. The new Death Egg is a hollow sphere built above and around the Little Planet similar to a Dyson sphere, the hypothetical Dyson sphere is designed to absorb energy from a star; this, presumably, is also the method which Eggman uses to power his latest space station. Sonic and Tails Defeat Dr. Eggman and Metal Sonic and the Death Egg mk.II Zone's power drains out leaving Little Planet still trapped inside it.
Appearances in Other Media
Sonic the Comic
In Sonic the Comic, the Miracle Planet appeared in the adaptation of Sonic CD, and then made recurring appearances throughout the series. It was consistently referred to as the Miracle Planet, save for a single mention in the backup Sonic's World story of Sonic the Comic #25 ("Prologue: Once Upon a Planet...") that some people know it as the Little Planet.
In its first appearance, Robotnik cyber-formed the entire Miracle Planet to be used as a power source for Metallix, the Metal Sonic. Sonic managed to defeat Metallix and restore the planet to normal by using a Time Stone.
Some time later, the Miracle Planet was taken over by the Brotherhood of Metallix. It was again covered in machinery, this time making it appear like a giant Metallix head, and used as a staging ground for the Metallix's attempts to conquer Mobius. Their plans were thwarted by Sonic and Chaotix, and the Miracle Planet was subsequently returned to normal yet again.
Little Planet appear in Archie's Sonic the Hedgehog comic book series and its spin-offs, although it has yet to be fully introduced. Much like in Sonic the Hedgehog CD, Little Planet is the hosts to the Time Stones, and appears over Never Lake once a year for one month. It is closely kept as secret by citizens of Albion and the current king of Mercia Rob o' the Hedge himself.
Locations on the Little Planet
- Palmtree Panic, a lakeside palm tree resort with invisible standing blocks and vertical ramps.
- Past, very much like the Present, but with distinctive primitive vegetation and overall landscape.
- Present, a nice grassy plain with some hills and palm trees.
- Bad Future, the lake and air are polluted, pipes are scattered all over, the trees are robotic, and the grass is dead, colored orange.
- Good Future, almost exactly like the Present, but there are pink stars and is benevolently robotic towards the nature of the area.
- Collision Chaos, a pinball-themed stage with bumpers and spikes at every turn.
- Past, a large forest.
- Present, like Palmtree Panic at dawn, but with some mechanical objects such as pipes and a golden concealed sky.
- Bad Future, contains a dark sky, and several mechanical "enhancements."
- Good Future, much like the Present, but all mechanical objects are gone, the sky is visible, and there is more plant life.
- Tidal Tempest, a subterranean underwater labyrinth filled with vacuum pipes.
- Past, a prehistoric volcano. Strangely, it does not have any magma or lava.
- Present, old ruins in a watery cave.
- Bad Future, a rusty, broken sewage system.
- Good Future, a bio-mechanical greenhouse and aquatic ecosystem with various flora.
- Quartz Quadrant, a mine-like cave with conveyor belts.
- Past, set inside the cave (which has less gems), and next to a large peaceful lake.
- Present, a gem-filled cave.
- Bad Future, an industrial city inside a gigantic cave.
- Good Future, a city with tall skyscrapers and the quartz intact.
- Wacky Workbench, a large mechanized factory featuring electrical conduits and an electrified floor.
- Past, a construction site near a mountain.
- Present, a factory filled with strange-looking machinery and pipes.
- Bad Future, a dark, rusted, overworked and neglected factory.
- Good Future, a brightly designed factory, with safer technology and less hazards.
- Stardust Speedway, an area containing a complex network of highways.
- Past, a jungle filled with large vines and what appears to be some ancient buildings (along with a cathedral sealed with a dome).
- Present, a city with golden highways, a glimmering skyline, and a giant Robotnik statue under construction.
- Bad Future, an industrialized, neglected city with polluted air, bleak storming crimson skyline, blue highways, and a finished Robotnik statue.
- Good Future, a carnival-like city with purple highways, ocean skyline, and a grand purple mansion in the distance.
- Metallic Madness, Robotnik's personal base, filled with mechanical contraptions.
- Past, the base still under construction.
- Present, a typical Robotnik Zone. Fully metallic and with tons of traps and robots.
- Bad Future, the base is rusty and falling apart.
- Good Future, a peaceful city with lots of plant life.
- The fact that the Bad Future of Stardust Speedway appears in games after Sonic CD can be contributed to the fact that Little Planet does not follow standard rules of time. 
- ↑ Sonic the Comic #24 to #28, "The Sonic Terminator"
- ↑ Sonic the Comic #59 to #62, "The Brotherhood of Metallix"
- ↑ Sonic the Comic #67 to #72, "The Return of Chaotix"
- ↑ Sonic the Comic #79, "Return to the Miracle Planet"
- ↑ Sonic the Comic #61, "The Brotherhood of Metallix, Part 3"
- ↑ Sonic in Sonic CD US manual page 2: "I heard that the planet's full of places that are completely ignored by the passage of time!" (manual scan)
- Little Planet in Mobius Encyclopedeia