The Mushroom Planet is a location that appears in the Sonic the Hedgehog film series produced by Paramount Pictures and its spin-offs. It is a planet in the Earth's universe that, like its name implies, is filled with mushrooms.
The Mushroom Planet has a muggy brown sky with a piercing sun, and it seems to possess at least two moons. The planet has a breathable atmosphere but is otherwise uninhabited by animal lifeforms. The surface of the planet shows signs of a rocky terrain with the occasional cave entrance on the surface, but is otherwise covered in flora like yellow-brown moss, small brownish-green bushes and, of course, mushrooms in all sizes that are so dominant that they grow on top of each other. According to Sonic, the mushrooms on the Mushroom Planet are "gross" and "smelly". There is also water on the planet.
Befittingly, the planet houses a vast variety of mushroom plants: some mushrooms are edible and rich on nutrition (although ingesting certain types may leave the consumer in a temporary trance) while others have taken on the characteristics of carnivorous plants. One breed of the latter in particular are blue mushrooms with teeth sharp enough to piece the human skin that will pop out from inside their stalk when their top parts are plucked. These mushrooms can grow from a miniscule size to the size of an adult human. However, like most plants, they are vulnerable to fire.
Sonic the Hedgehog
Surviving his arrival on the planet, Robotnik would spend his time looking for a way back to Earth. However, after spending three months on the planet, Robotnik lost his grasp on his sanity. Eventually, with some remains from his Eggpod and one of Sonic's re-energized quills, Robotnik resumed scouring the Mushroom Planet with a stone he replaced Agent Stone with, confident that he would be able to return to Earth soon.
Sonic the Hedgehog 2
On his 243rd day on the Mushroom Planet, Dr. Robotnik had his morning routine while drinking mushroom tea. Soon after, he would finish building an energy beacon, powered by Sonic's chaos energy-infused quill, from his Eggpod to attract visitors in an attempt to return to Earth and exact his revenge against Sonic. Upon hooking Sonic's quill up to his invention however, Robotnik created an energy pulse so great that it spread far into space and knocked himself out. Later, at night, three alien scavengers appeared thanks to a Ring. Awakening soon after, Robotnik took them out with traps he had set up on the Mushroom Planet. When Robotnik tried to escape from the planet through the scavengers' Ring however, Knuckles the Echidna emerged from the portal. Upon seeing Sonic's quill in Robotnik's hand, Knuckles demanded to know where he got it from. In response, Robotnik told him where and offered to help lead Knuckles to Sonic. Agreeing to the deal, Knuckles got Robotnik off the Mushroom Planet.
Sonic the Hedgehog: The Adventures of Sonic & Donut Lord
In Sonic the Hedgehog: The Adventures of Sonic & Donut Lord, after accidentally revealing his presence on Earth, Sonic planned to go into hiding on the Mushroom Planet. Fortunately for him, this plan never came to be, as he eventually found a new home with the Wachowski family.
Sonic the Hedgehog 2: The Official Movie Pre-Quill
While stranded on the Mushroom Planet, as Dr. Robotnik reflected on his current situation and Sonic, the doctor vowed that he would survive on the Mushroom Planet and find a way back to Earth. As he looked for food to sustain him while he rebuilt his Eggpod, Robotnik found an edible type of mushroom, which he began collecting. As his search took him into a cave with a surplus of those mushrooms however, he ended up disturbing some of the local carnivorous mushrooms. Despite them posing a threat to him, Robotnik obstinately kept plucking mushrooms until he had awoken a swarm of carnivorous mushrooms. Even when swarmed by these plants however, Robotnik refused to let himself die here. As he then came face-to-face with a giant carnivorous mushrooms which tried intimidating him, Robotnik used his hand-made, wrist-mounted flamethrower to destroy it. Robotnik then proclaimed as he left the cave that he would destroy anything that gets in his way on this planet and return home to get revenge on Sonic.
- The Mushroom Planet is most likely based on Mushroom Hill Zone from Sonic & Knuckles.
- The symbol on Sonic's map for the Mushroom Planet is of silhouettes of mushrooms from the Zone.
- In Sonic the Hedgehog: The Official Movie Novelization, it was stated that the Mushroom Planet consisted of a giant forest with mushrooms in every size, similar to Mushroom Hill Zone.
- In the first trailer of the Sonic the Hedgehog film, the sky of the Mushroom Planet was turquoise, resembling that from Earth. However, in the actual film, it is light brown colored.