Phaaze

Phaaze is the final location Samus Aran visits in Metroid Prime 3: Corruption, and, by extension, the entire Metroid Prime trilogy. It is the source of all Phazon. From Phaaze, the Leviathans are grown and sent into space to corrupt planets, such as Tallon IV, Aether, Norion, Bryyo, Elysia, and the Space Pirate Homeworld.

Features and History
Phaaze is a living, sentient planet. Inside the planet is a womb where Leviathans are born and grow. Once they mature, they leave Phaaze and corrupt planets with Phazon. As the Leviathan corrupts the planet, it takes control of a native creature and corrupts it to protect its core.

The planet is completely composed of Phazon. This may mean that there could be undiscovered strains of Phazon. The existence of Black Phazon Crystals was previously unknown until discovery of the planet.

Phaaze was first discovered by a Chozo Searcher on Elysia. A once thought lost satellite began transmitting data on Phaaze. However, this data only revealed small details about the planet. The Chozo Searcher learned that Phaaze was somehow "alive". However, the data being collected was lost before the Chozo could analyze it. Further research about the planet was next to impossible, as Phaaze was incredibly far away, even for Chozo space travel standards.

After this, Phaaze would be undetected for many years. The next time that living beings not born of Phazon would lay eyes on it would be when Dark Samus brought the Space Pirates there. Following the Space Pirate attack on the GFS Valhalla, Dark Samus implanted Aurora Unit 313 into the planet itself, allowing her to control the planet and its resources.

Finally, the Galactic Federation tracked the origin of the Leviathans to Phaaze. They began preparations to travel there to put an end to Phazon's destructive power. After taking control of a Leviathan and warping there, the Federation engaged the Space Pirate fleet in orbit above the planet while Samus headed down there to find Dark Samus.

After traveling through Phaaze's alien depths, Samus confronts Dark Samus. After they do battle, Dark Samus calls forth Aurora Unit 313 and merges with it. Samus destroys the corrupted Aurora Unit that is connected to Phaaze. Due to the symbiotic nature of this relationship, the destruction of the Aurora Unit causes a chain reaction that culminates in Phaaze's explosion. As a result, all Phazon is destroyed.

Life
All life on Phaaze is Phazon-based. Phazon Metroids and Hopping Metroids are abundant, as well as Phazon Puffers, Phazon Hoppers, and Phaz-Ing. In addition to this, many unknown life-forms inhabit Phaaze. An infant Leviathan can be found on the planet, as well.

Husks of creatures similar to Metroid Prime can also be found behind the Leviathan womb in the Genesis Chamber. It is likely that, as on Tallon IV, the Phazon-rich environment of Phaaze caused the Metroids present to mutate into this ultimate form.

Dark Samus also appears on Phaaze, as it is her base of operations, as well as technically being her homeworld. Aurora Unit 313 has been implanted into the planet's core.

Samus's arrival
After arriving on Phaaze, Samus' Phazon corruption reaches near-critical levels, causing her to remain in hypermode permanently. Samus becomes so corrupted that her gunship no longer recognizes her as Samus Aran, therefore denying her access to her ship for the rest of the game.

Also, all energy tanks are "filtered", and a yellow bar at the top of the HUD is there in its place. As Samus is exposed to Phaaze's atmoshpere, this bar will gradually fill up. Taking damage also fills up the meter. The bar will deplete when units of "Anti Phazon" are absorbed, or when using the Hyper Grapple to expel energy/Phazon into an enemy. When the meter is maxed out, Samus becomes fully corrupted, and the game is over.

Bosses
Dark Samus

Aurora Unit 313