This thing is out of control. Hurry before it destroys the entire station...
— Adam Malkovich
Nightmare is an organism outfitted with mechanical devices capable of manipulating gravity encountered by Samus Aran in Bottle Ship and the B.S.L research station. It can generate a gravitational field that impedes Samus's movement and diverts weapons fire. Nightmare is also capable of firing beams of energy and homing projectiles.
Nightmare was created by Biologic Space Labs researchers to be used as a weapon. Its appearance on the Bottle Ship suggests that either more than one of it has been created or that the creature had been built earlier by Galactic Federation researchers and was recovered on the Bottle Ship before the Bottle Ship was destroyed and rebuilt on the B.S.L research station.
Metroid: Other M
On the way to Sector Zero, Samus encounters areas of the Cryosphere with irregular gravity. It is soon revealed that this gravity is a result of the presence of Nightmare, who descends from the ceiling when Samus attempts to enter its room. While its gravity generator spins, Samus's movement is impeded, and Missiles are ineffective until she can freeze the generator; after that, she must fire Missiles at its mask until the cycle repeats again. Once enough damage has been dealt, the mask will shatter, revealing Nightmare's grotesque, literal, baby-face. After that, it will fall to the ground, seemingly defeated.
Upon Samus's return from the sector, Nightmare attacks Samus once again; this time, it will send out black holes that draw in all of Samus's weapons fire. Once defeated, its body will fall apart and rest on the ground until the post-credits sequence, when it will have disappeared, presumably transferred to the Biologic Space Labs research station for its appearance in Fusion.
Shortly after Samus acquires the Ice Missile in Sector 5 (ARC) Nightmare's shadow can be seen ominously strafing the sector in the background, then in subsequent visits to Sector 5. After Samus acquires the Plasma Beam, Adam detects massive damage in Sector 5, later learning that the damage was caused by Nightmare, who he suspects has become a host to the X parasites.
When Samus battles Nightmare, it will fire six beams at first. After Samus damages Nightmare's gravity manipulator, Nightmare will activate it, heavily increasing the effects of gravity. Nightmare won't be unaffected by the change in gravity, as its movements will slow and it will only be able to fire two beams at a time. The creature will continue to fire energy beams while Samus is impeded by the intense gravity. Nightmare's intense gravity fields will be able to force Samus's Missiles to the ground, limiting their capabilities, but her newly-acquired Plasma Beam is unaffected.
After Samus damages the manipulator enough, it and the plate covering Nightmare's face will be destroyed. Nightmare will then move in erratic patterns attempting to ram Samus as well as firing energy beams. Nightmare's movements will make the Space Jump a powerful tool to evade Nightmare's attacks. After Samus inflicts further damage to Nightmare, its Core-X will become exposed, allowing Samus to destroy it and attain the Gravity Suit from it.
Super Smash Bros. for Wii U
- In Metroid Fusion, if Samus has her beam charged while Space Jumping, she can pass through Nightmare's arms without taking damage.
- Samus's beams are unaffected in Fusion though they are attracted to Nightmare in Other M.
- "It's gotten worse. The damage seems to have been caused by a creature kept here by the researchers, who named it... the Nightmare. Apparently, it was a bio-mechanical organism designed for military applications... It possesses uncommon power and can manipulate gravity. We must assume that it's become an X-host. We have no choice. You must find it and defeat it. I can't confirm the location." —Adam Malkovich (Metroid Fusion)
- "What? You've restored Plasma Beam functionality? ...Most unexpected. Even so, continue to avoid the SA-X. It, too, may be stronger. And you still lack a few abilities crucial to survival... Wait.. Wait a second... More trouble. Hold on. ..................................................... ... I've isolated the cause. There's been an explosion in the ARC Data Room... Samus, go to Sector 5." —Adam Malkovich (Metroid Fusion)