Phaaze

Phaaze (so named by the Space Pirates and the Galactic Federation) was a sentient planet and the source of all Phazon. It is the final location Samus Aran visits in Metroid Prime 3: Corruption, and by extension, the entire Metroid Prime Trilogy. From Phaaze, the living meteors known as Leviathans were grown and sent into space to corrupt planets. The known planets hit by Leviathans were Tallon IV, Aether, Bryyo, Elysia, and the Space Pirate Homeworld, though all were eliminated. A Leviathan was also sent to Norion, but it was destroyed before it hit the planet.

Features and History
Phaaze is a sentient planet. Within the planet are Serpentine wombs 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 manipulates it to protect its core. After many 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 present on Phaaze prior to its destruction. The existence of Black Phazon Crystals was previously unknown until discovery of the planet.

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". Unfortunately, the data being collected was mysteriously lost before the Chozo could properly 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 Battleship circling the Pirate Homeworld 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 confronted Dark Samus. After they did battle, Dark Samus called forth Aurora Unit 313 and merged with it. Samus destroyed the corrupted Aurora Unit connected to Phaaze, and due to the symbiotic nature of this relationship, the destruction of the Aurora Unit caused a chain reaction that culminated 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 (a theory is that they were brought there by the Space Pirates in an effort to better protect the planet) 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. All species were rendered extinct by the destruction of the planet.

Husks that are identical 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 on the planet, but only one was seen in the entire game. The presence of the husks may indicate that the room was the birthplace of the Metroid Prime creature on Tallon IV.

Dark Samus also appears on Phaaze, as it is her base of operations and apparent 'homeworld' (based on the Space Pirate Data The Source Discovered). She can absorb energy from the planet itself to heal herself in battle. Aurora Unit 313 had been implanted into the planet's core.

A list of creatures that can be found inhabiting Phaaze is below:
 * Aazelion
 * Aurora Unit 313
 * Dark Echo
 * Dark Samus
 * Fungus
 * Glow Stem
 * Hopping Metroid
 * Jelsac
 * Leviathan (unseen, presumably scattered below Phaaze's surface)
 * Leviathan Infant
 * Leviathan womb
 * Massive Tentacle
 * Maw
 * Metroid Egg (heavily saturated and mutated by Phazon)
 * Miniroid
 * Phaaze Door
 * Phaz-Ing
 * Phazon Fungus
 * Phazon Hopper
 * Phazon Metroid
 * Phazon Puffer
 * Phazon tendril
 * Phazon Vine
 * Space Pirate (an armada guards Phaaze)
 * Tangle Weed
 * ULF 3
 * ULF 7

Samus' arrival
Seconds after arriving on Phaaze, Samus' Phazon corruption reached nearly critical levels, causing her to remain in Hyper Mode permanently. Samus became so corrupted (though not completely, as she still retained her free will) that her Gunship no longer recognizes her, 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, showing her Phazon level. As Samus is exposed to Phaaze's atmosphere, this bar will gradually fill. The amount of time it takes to completely fill up depends on the number of Energy Tanks collected throughout the game; the more Samus has acquired, the more time space in the bar and time she will have. Taking damage also fills the meter. The bar will deplete when "Anti-Phazon Units" are absorbed, when Phazon Puffers absorb her energy for an attack 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 as Samus turns into a new Dark Samus.

Bosses

 * Dark Samus
 * Aurora Unit 313

Metroid Prime Trilogy art booklet
"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."''

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

 * As mentioned above in the Biology section, the presence of Metroids, along with hives, as well as the carapaces of the/a Metroid Prime on the sentient planet is considered a great mystery for the following reasons:
 * The Chozo created the Metroids and placed them on planet SR388 (making it their homeworld), and the bird-like race had no knowledge concerning Phaaze during that time, let alone its location. If the Metroid Prime found on Tallon IV was truly born from a larval Metroid present on Phaaze, it leads to the question of how the floating organism(s) managed to arrive on the Phazon planet all the way from SR388.
 * The theory of Space Pirates bringing their Metroid specimens to Phaaze when Dark Samus gave them its location can explain the surprisingly large number of Metroids living on said planet. However, this would pose a problem if Metroid Prime, as some speculate, originated from Phaaze.
 * Since the events of Metroid Prime 2: Echoes imply that Dark Samus stole several Metroids from the Space Pirates, it is possible that she took some back to Phaaze with her. This would mean that she would have had to have taken the Metroids back to Phaaze when she disappeared for a time after brainwashing the Space Pirates on board the Colossus. However, the Metroids are not mentioned in the Space Pirate Data and it seems unlikely that the massive number of Metroids on Phaaze could have been created in the timespan between Dark Samus's journey to Phaaze and Samus's arrival.
 * Some assume the Metroid Prime was born on Tallon IV, from a larval Metroid brought to said planet either by the Chozo or the Space Pirates. This theory would imply that Metroids never existed on Phaaze until Space Pirate intervention. But the lack of any lore mentioning the existence of a single Metroid living among the Chozo and the fact that the Cradle's containment field kept anything from going in or out of the Impact Crater (where the Phazon Core was), puts the theory in doubt. Also of curiosity is the presence of Metroid Prime-like husks in the Genesis Chamber, implied to have been shed by the creature encountered on Tallon IV.
 * 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 is the one to inform Samus that the Galactic Federation named this planet "Phaaze". However, certain Space Pirate Data entries that can be uncovered before the transmission 242 gives use the same name.
 * AU 242 suggests the Pirate Homeworld may have also become a secondary Phaaze due to the mass corruption of Phazon and possibly transformed the said planet into another Phazon source as well.
 * Phaaze is the second planet to be destroyed in the Metroid series, preceded by Dark Aether, then followed by Zebes and SR388.
 * Phaaze played a crucial role throughout Metroid Prime Trilogy, being responsible for the "Great Poison" on Tallon IV in Metroid Prime and the splitting of Aether into two planets in Metroid Prime 2: Echoes.
 * When Samus first enters Phaaze, a cutscene is played of her ship entering the atmosphere. This is only one of two instances in which the cutscene is seen, the other being the arrival on Norion.
 * There is a possible mention of Phaaze in the Chozo Lore "Great Poison", where the Chozo theorize one planet once was coated with the Great Poison, and meteors from it spreading the Great Poison to the far corners of the universe, though this is primarily mentioned as a terrible "what if" from the Lore's writer.