Metroid Prime
Metroid Prime appeared in Tallon IV shortly after the impact of the Leviathan, a living Phazon meteor, fused with a Metroid unfortunate enough to cross its path. It caused severe damage to the Chozo colony before the Artifact Temple was built to contain Metroid Prime inside the impact crater of the Leviathan. According to the NTSC version of "Metroid Prime", Space Pirate miners eventually discovered the creature, eventually dubbing it "Metroid Prime" after containing it with security units and drones brought to their laboratories to perform experiments. Metroid Prime eventually broke free, and managed to assimilate several weapons and defense systems from fallen security units before going back to the impact crater However, the PAL and "" versions deny this, with the Pirate Logs only stating the Pirates picked up life signals coming from within the Artifact Temple. After Samus gets all of the artifacts, she is able to enter the impact crater and fight Metroid Prime. After its defeat, the creature takes Samus' Phazon Suit to reconstruct itself into a body similar to hers, resulting in the being referred to as "Dark Samus".