Metroid Prime

Metroid Prime is a heavily-mutated Metroid and the primary antagonist/final boss of the first Metroid Prime game. The exact origins of this creature are unknown, but it was prophecized by the Chozo colonists of Tallon IV that an entity from the stars would collide with their world, bringing with it a Great Poison that would corrupt and destroy all life.

Chozo Prophecy
A Chozo prophecy foretold that their adopted world of Tallon IV would become infested by a great evil. This evil, known to them as the Worm, would devour the planet from within by bringing a Great Poison, unless a great Defender delivered the planet from its evil.undefinedSome great time after the prophecy, the Chozo reached ascendance while living in the tranquility of their world; their bodies were cast away while their essences entered a new plane of reality.

Years after their ascendence, the prophecy came to fruition: a Leviathan from the planet Phaaze crashed onto Tallon IV and released Phazon, a highly poisonous and mutagenic substance. The Phazon seeped into the soil and life of Tallon IV, destroying the ecosystem and violently mutating the life that could endure. The remains of the Chozo were also greatly affected, so much so that their consciousness was pulled back the other side of reality.

Seeing the evil that was corrupting their former home, the returning Chozo created a temple, known to them as the Cradle, to contain the Leviathan and the continued spread of Phazon. In order to ensure a seal around the cradle, as well as provide their prophesized Defender access in, they created and scattered twelve key-like Artifacts known as the Cipher.

Their efforts with the Cradle only stopped the brunt force of Phazon; Tallon IV now suffered the fate of a slow death as the exposed poison spread out. The returned Chozo concluded that Tallon IV was doomed unless saved by their prophesized Defender. As ethereal forms in a tangible world, their perception of time was now non-linear; past, present, and future wove in and out of view. With this perception of time, they could see their adopted Hatchling haunting, prowling, and lurking in the planets' corridors. They pondered if she was their Defender, and left behind Power Suit modules in hopes that one day she would fulfill the prophecy and deliver the planet from death.

Eventually, the Chozo who were brought back succumbed quickly to Phazon corruption. Known to the others as the Turned, they hated, destroyed, and rejected everything in sight, including their former peers; their ultimate goal was to undo the Cipher and let the Phazon spread.

Eventually, the Space Pirates landed on the planet, and tried to comprehend the purpose of the Cipher and Artifacts, without success. They then tried to destroy the Cradle, known to them as the Artifact Temple, but failed again. The Pirates eventually discovered Phazon, and as soon as Science Team identified its unique abilities, began mining operations to harvest it, beginning exploration of its mutagenic properties with flora and fauna, even going so far as to include Metroids and their own species. As their ambition with the substance grew, they tried to use other alternatives to get past the Cipher, including drilling underneath the Artifact Temple lock. This proved futile, as this attempt revealed that the Cipher generated an encompassing force field. However, the Pirates did detect a powerful life form that was rapidly consuming Phazon inside the crater.

Samus' arrival
When Samus Aran arrived on Tallon IV, the planet was heavily corrupted by Phazon. She explored the planet, exterminating many of the corrupted creatures and destroying the Space Pirate base. She eventually collected the twelve Chozo Artifacts and gained access to the Impact Crater, though she had to fight off Meta Ridley beforehand.

Inside, instead of the normal blue Phazon seen throughout the planet, Red Phazon could be seen. This Phazon was 86% stronger than normal Phazon, strong enough to mutate Metroids into Fission Metroids, and to cause damage to Samus' suit, despite the protection given by the Phazon Suit. As she progressed through the Impact Crater, she encountered Metroid Prime.

Exoskeletal Form
The first form of Metroid Prime is completely encased in a thick black carapace, save for its glowing red eyes. It uses a shielding system where the color of the (initially) grayish-white markings on its body indicate what beam is its weakness. The same can be said of the color and nature of the beam it fires from its massive maw (which spans the bottom of its entire carapace). Purple represents the Wave Beam, blue-white represents the Ice Beam, red represents the Plasma Beam, and yellow represents the Power Beam. Samus must switch to the beam (or beam combo) required and fire at Metroid Prime's human-like visage to damage it. After a set amount of damage, Metroid Prime will retaliate by closing the lid where its visage is exposed before attempting to ram Samus, which she can avoid by entering Morph Ball form and rolling into grooves in the ground under the creature. It will also attack with Ultrafrigid Breath, Multi-Missiles, Snare Beams, and Particle Wave Projectors. As Metroid Prime takes more damage, it retreats into deeper caverns, using stronger and stronger attacks as it goes. Its movements and attacks become progressively more erratic as well, as it will shift screens more frequently and its attacks become more unpredictable. Eventually, it crawls toward one final pit and falls, and Samus follows it.

Core Form
When Samus lands, she finds Metroid Prime's exoskeleton open with its top missing and the armor plating oozing Phazon. Metroid Prime flies out of the cast-off body in its second form, the core essence of Metroid Prime. In its second form, Metroid Prime is only vulnerable to pure Phazon. Aside from the humanoid face, the creature now somewhat resembles a six-tentacled squid with highly developed nuclei, similar to a Hunter Metroid and (especially) a Phazon Metroid, though more brain-like in appearance. It will use its tentacles to shoot waves of energy throughout the room which Samus must jump over to avoid, and it will spawn various species of Metroid. There are several ways for Samus to deal with the Metroids: she can use a Power Bomb to kill them, she can run past them and use the Phazon Beam to kill them, or she can resort to standard Metroid-killing tactics and use the Ice Beam to freeze them, then shatter them with a Missile. However, this last tactic only works the first two times Prime spawns Metroids; afterwards, it only creates Fission Metroids. Whenever it creates a Metroid, Metroid Prime will also create a small pool of Phazon. After Metroid Prime creates a pool of Phazon, it may disappear from the Combat Visor and must be tracked with either the Thermal Visor or X-Ray Visor. With the use of the Phazon Suit, Samus can stand on these pools and enter Hyper Mode. She can then fire Phazon at Metroid Prime by the use of the Phazon Beam, greatly damaging it. Eventually, it will completely destabilize.

Once Samus has defeated Metroid Prime's second form, it morphs into an odd-looking blob, similar to a Metroid or a Core-X from Metroid Fusion. Tentacles will come out of it and grab Samus, pulling her towards it. Samus pulls back, and is eventually separated from her Phazon Suit, which is pulled into what remains of the Metroid Prime. This leaves her in her Gravity Suit. All other sources of Phazon in the general vicinity explodes, causing the entire cavern to collapse. She calls in her ship using the obscure controls on her arm cannon, and leaps from the collapsing structure onto her hovering gunship. The Hatchling has fulfilled the prophecy.

Dark Samus
Though Samus believed that Metroid Prime had been destroyed, it was able to pull itself back from the brink. As it destabilized, it grabbed Samus with its tentacles and managed to rip away the Phazon Suit, taking fragments of Samus' DNA with it. Absorbing the Phazon Suit and Samus' DNA allowed the creature to take on a new form similar to that of its killer, and it would return to hunt the Hunter as "Dark Samus".