Dark Water

Dark Water is a substance encountered on Dark Aether in Metroid Prime 2: Echoes. As the name implies, it is that world's equivalent of conventional water, and usually (although not always) exists where water is found on Light Aether. It is highly corrosive and severely damaging to unprotected matter from the light dimension, although many Dark creatures such as the Hunter Ing, Flying Ing Cache, Dark Phlogus, Chykka, Dark Shredder and Dark Grenchler can and do spend much of their lives immersed within it without any ill effects. In this regard, it is similar to Dark Aether's atmosphere, although its destructive effects are not alleviated by the fields of Light Beacons or Light Crystals. Physically, the substance seems to be a near-opaque purple liquid with an abnormally high viscosity- before acquiring the Light Suit (which also protects from Dark Water's corrosive effects), Samus is able to walk across its surface without sinking into the fluid (although after gaining the Suit, she is able to maneuver within it exactly as she would in regular water). The increadible amount of damage caused by contact with this substance has lead many of the creatures immune to its effects to spit or splash Dark Water at their opponents as an offensive weapon.

It is unknown whether Dark Water is chemically identical to conventional water and gains its unusual properties from another material dissolved or suspended within it or from the nature of the Dark Dimension itself, or whether it is an entirely different substance.