Dark Samus

Dark Samus is a dark copy of the hero Samus Aran, in the Metriod Prime series. Dark Samus is a being composed mainly of Phazite, a form of Phazon. Dark Samus is refered to as 'she', but it is unknown if she has gender. In Metroid Prime 3: Corruption, she manages to transform an entire planet into a source of Phazon. There, she developes the Leviathan Seeds: living creatures that have been bioengineered to form rooms within their bodies, and carry massive amounts of Phazon. She plants a seed first into the Pirate Homeworld. Then, Dark Samus, along with the help of the space pirates, leads an attack on the Galactic Federation, and manages to implant one of the gigantic Seeds in the planet Bryyo. The protagonist Samus manages to stop one seed from crashing into Norion, a planet important to the Galactic Federation. Dark Samus appears then and hits Samus and her bounty hunter allies and implants phazon within their bodies. Soon after, a Seed is implanted into the planet Elysia. The Seeds begin to corrupt the planets and the forms of life (In Elysia's case). To be destroyed, Samus enters them, and must destroy a monster who is powered by the Phazon energy inside (probably inside a lung-like cavity). Every time she destroys a monster, the phazon released begins to corrupt her farther.