Cylosis is given as Sylux's origin in the opening cinematic of Metroid Prime Hunters. Since Sylux is surrounded in mystery, it is debatable whether Cylosis is Sylux's actual homeworld, or simply where Sylux stole the armor, Delano 7, Shock Coil, and Lockjaw that the Bounty Hunter uses.
The opening movie cinematic in the game shows a location that may represent Cylosis as a plain and lifeless-looking surface, with blue-gray dust (or possibly snow) storms. A sun or star can possibly be made out from behind the veil of clouds at the beginning of the scene, in the top-right corner above a mountain.
Etymology
Cylosis is the circulation or streaming of the cytoplasm within some living cells.
Gallery
Sylux's intro during the opening cinematic of Metroid Prime Hunters, which may depict Cylosis.