It is commonly believed and occasionally implied that this substance is lava. However, it is impossible to tell due to Return of Samus lacking the necessary color palette, as it plays on the Game Boy, and as such is completely in black and white or shades of green along with the Game Boy Player coloring it blue. The instruction manuals for Metroid II (both English and Japanese) only refer to it as a "dangerous liquid", but depict it as red, like lava. The Super Game Boy Player's Guide further complicates the matter by stating the presence of both acid and lava within the caverns of SR388. In Metroid Fusion, the area known as Sector 1, featured on the Biologic Space Laboratories research station and designed to be a perfect imitation of the environment found on SR388, suggests the liquid to