Year 20X5, in the Cosmic Calendar, was the year in which the Space Research Vessel Marina was attacked by the Space Pirates. The ship had been returning to Galactic Federation with samples of a newly discovered life-form before it was attacked. This life-form was called the Metroid, and it was discovered to have parasitic traits, including the ability to siphon the life energy of any living organism, leaving nothing but a brittle husk. The Space Pirates, desiring to use the Metroids as bioweapons, seized the creatures and made haste for their stronghold on planet Zebes, where they began to clone the Metroids by exposing them to beta rays. The Galactic Federation located the base, Tourian, but was unable to seize it. They sent in legendary Bounty Hunter Samus Aran to Zebes to destroy the Me