Nightmare (Metroid)

The Nightmare is a genetically engineered experimental bio-weapon developed by a secret Galactic Federation Research Team operating aboard the Bottle Ship. The creature uses a strange natural ability that allows it to control gravity, which is enhanced by the cybernetic armor it is housed within.

Information
The Nightmare was created to be used as a destructive bio-weapon and strike fear in the hearts of enemies (if its appearance would attest). The armored exosuit comprises of a wormlike, box-shaped body with two huge winglike arms lined with laser cannons. Beneath the body is a globe-shaped device that Nightmare uses to alter gravitational pulls and sustain flight. The face of the creature is hidden behind a eerie mask that looks like a ghoulish face, lined with patterns resembling stitching. Its vocalizations sound much like a banshee's wail. Once the gravity well device and mask sustain enough damage, the latter breaks away to reveal the Nightmare's true form; a green sluglike creature with six eyes. Its attacks become much more erratic and harder to evade when its face is exposed, but with the mask removed, the creature can be attacked directly. The Nightmare housed on the Bottle Ship was held in a room in the Cryosphere Sector that preceded the access lift to Sector Zero.

X Parasite Replica
After the original Nightmare was killed by Samus Aran on the Bottle Ship, another was created on the B.S.L. Station near SR-388, held within the sub-zero containment area, Sector 5 (ARC). This specimen, along with many other creatures held aboard the station, was infected and presumably killed by the X Parasites that ran loose throughout the station. The X, being able to absorb and mimic the DNA of creatures that they infect, were able to assume the form of Nightmare after infecting it. It then began a rampage through Sector 5, which prompted Samus to track it down and kill it. Absorbing the Nightmare's Core-X granted the Gravity Suit feature to Samus's Fusion Suit.