Poison gas

Poison gas is a purple, toxic gas that exists only on Dark Aether. It is encountered during the second phase of the final battle against the Emperor Ing during Metroid Prime 2: Echoes.

The Emperor Ing enters a chrysalis covered in vents, which begin to expel this gas into the room. While it looks similar to the dark vapor emitted by Ingclaws, it is corrosive even to the Light Suit. However, the rate that Samus's energy is drained by exposure to the gas is slower than the Ingclaw vapor. The gas makes it unsafe for Samus to remain on the floor, so to avoid it she must scale the Emperor Ing's body using her Spider Ball. To bring the beast out of its chrysalis, Samus has to attack its tentacles using her Bombs. As Samus destroys the tentacles, the vents emit more gas into the Sanctum, which causes the height of the gas to fluctuate and completely cloud the floor. There are instances where the gas rises to such a high level that only the small area near the cocoon's top is left uncovered. Samus can wait there for the gas to recede so she will be safe, but this makes her easy prey for the Inglets that attack her on the chrysalis body. Once the Emperor Ing's mutation is complete and the chrysalis explodes, the gas fades.