Phaaze

Phaaze is the final location Samus Aran visits in Metroid Prime 3: Corruption, and 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. The known planets hit by Leviathans are: Tallon IV, Aether, Bryyo, Elysia, and the Space Pirate Homeworld.

Features and History
Phaaze is a sentient planet. Within the planet is a womb where Leviathans are born and grown. Once they mature, they leave Phaaze and corrupt planets with Phazon. Leviathans leave Phaaze every 100 years. As the Leviathan corrupts the planet, it takes control of a powerful local bioform and corrupts it to protect its core. After a couple of years, the corrupted planet becomes a Phaaze clone.

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. The orange Phazon which was encountered in Tallon IV's Impact Crater makes an appearance here, as a strain of Red Phazon, Phazite, which was probably assimilated into the Leviathan which impacted Tallon IV.

Discovery
Phaaze was first discovered by a Chozo Searcher on Elysia. A once-thought-lost probe began transmitting data on Phaaze. However, this data only revealed minor details about the planet. The Chozo Searcher learned that Phaaze was somehow "alive". Seeing as how the Leviathans (living meteors) are produced in caverns with structures that resemble wombs, Phaaze could very well be a living creature. Unfortunately, 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.

Recent history
After this, Phaaze would be undetected for many years. The next time that bioforms exotic to Phaaze would lay eyes on it would be when Dark Samus brought the Space Pirates there. Following the Space Pirate attack on the G.F.S. 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 preparing 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 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 the destruction of Dark Samus and planet Phaaze itself.

Biology
Life on Phaaze is largely Phazon-based. Phazon Puffers, Phazon Hoppers, and Phaz-Ing are abundant, as well as, shockingly, Phazon Metroids and Hopping Metroids; the existence of Metroids (along with hives) on Phaaze is one of the greatest mysteries that exist within the Metroid series. In addition to these creatures, many previously unseen bioforms inhabit Phaaze, some that are even unidentifiable by Samus' scan visor. An infant Leviathan can be found on the planet, as well.

Husks of bioforms similar to Metroid Prime can also be found behind the Leviathan womb in the Genesis Chamber, though it is unknown if these are peeled/molted skin left by the Metroid Prime that dwelled on Tallon IV or if they belonged to other Primes living on Phaaze. It is likely there are more Genesis Chambers to be found on the planet. Dark Samus also appears on Phaaze, as it is her base of operations, as well as being her homeworld and can absorb energy from the planet itself to heal herself in battle. Aurora Unit 313 had been implanted into the planet's core.

Samus' Arrival
Seconds after arriving on Phaaze, Samus' Phazon corruption reaches nearly critical levels, causing her to remain in hypermode permanently. Samus becomes so corrupted (though not completely, as she still retained her free will) 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 "vented", and a yellow bar at the top of the H.U.D. is there in its place. As Samus is exposed to Phaaze's atmosphere, this bar will gradually fill. Taking damage also fills 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 maximized, Samus becomes fully corrupted, and the game is over, showing a disturbing new sequence where Samus, from the Phazon corruption, turns into a new Dark Samus.

MPT artbook
"No one knows when Phaaze was born.

''A planet completely unique in an infinite universe, unlike any that came before it. Phaaze was alive. A conscious, sentient being.''

''Like all living creatures, Phaaze did its best to ensure the continued survival and prosperity of its race. Every 100 years, seeds, similar in form to meteors, would be fired from Phaaze to planets far away. These seeds, these children of Phaaze, were called Leviathans. Leviathans had the ability to generate wormholes, allowing them to travel to galaxies unbelievably far away.''

''When a Leviathan strikes a planet, it creates a Phazon Core which emits a strong toxin called Phazon all over the planet. Phazon is a powerful substance with the ability to completely corrupt living beings through genetic mutation. Over the course of a couple years, Phazon corrupts the entire planet, at which point the planet is reborn as a Phaaze clone."''

Bosses

 * Dark Samus
 * Aurora Unit 313

Etymology
The planet's name is likely a play on the word phase, which is one part or portion in recurring or serial activities or occurrences logically connected within a greater process, often resulting in an output or a change. Phaaze acts as the final phase of the Metroid Prime Trilogy, though it triggered the events of the entire series prior to the plot depicted.

Trivia

 * The destruction of Phaaze due to the defeat of Aurora Unit 313 is very similar to the destruction of Zebes after Mother Brain is destroyed by Samus in Super Metroid.
 * Aurora Unit 242 says that the Galactic Federation have named the planet "Phaaze". However, in certain Space Pirate Lore, they call it by the same name, though 242 could have taken the data from the Pirates. These scans can be uncovered before the transmission 242 gives.
 * Phaaze is the first planet to be destroyed in the Metroid series, followed by Zebes and SR388.


 * Phaaze played a role in the entire Metroid Prime trilogy. It was responsible for the "Great Poison" on Tallon IV in Metroid Prime, it was the reason why Aether was split into two planets in Metroid Prime 2: Echoes, and is the final planet visited in Metroid Prime 3: Corruption.


 * If Samus had retained her Phazon Suit from the first Prime game, she could have theoretically been able to withstand the atmosphere of Phaaze, since its atmosphere is probably a gaseous form of Phazon. This is also likely true of Dark Aether.