SR388

Overview

SR388 is the first planet in which the Galactic Federation discovered the Metroid species. SR388 is a barren world whose surface is constantly bombarded by gamma radiation, making it impossible for almost any kind of life to exist there. The Chozo settled this planet many years ago, and carved out a network of tunnels under the surface of SR388, building cities underneath the surface. Most of the terrain on SR388 is barren and rocky, with old deteriorated ruins of Chozo cities dotting the underground caverns. SR388 experienced frequent seismic activity, causing the lava levels in the underground caverns to change as Samus Aran explored it in Metroid 2: Return of Samus. SR388 also played a part in Metroid: Fusion in the prologue, and is where Samus was infected by the X Parasite.

The Chozo, the Metroids, and the X

SR388 is thought to be the home planet of the Metroid species. In Metroid: Fusion, however, it was revealed that the Metroids are a species created by the Chozo to stem the growth and spread of perhaps an even more dangerous threat: the X Parasites. The X were able to infect creatures and take control of them, inheriting their thought processes and memories, and able to clone those creatures by simply splitting itself into two or more forms. If the X were to infect a sentient creature, they too inherited their ability for critical thought, making them an extremely dangerous threat. The Chozo realized this and created the Metroid species in order to combat the X. Metroids, instead of becoming infected by the X, simply absorbed them as energy, and thus became the primary predator of the parasite. After the Metroid species was wiped out on SR388 in Metroid 2: Return of Samus, the X began to multiply again, and infected Samus when she returned to the planet in Metroid: Fusion.