Phantoon

Phantoon (ファントゥーン Fantūn) is an ethereal, genderless specter that is both intangible and thus invulnerable to any form of attack, except for its single eye. It is this eye that, when open, serves as its connection to the mortal world and can be damaged. Ranging in size from four meters tall to ten times as large as Samus' ship, Phantoon resembles a giant cephalopod with a single eye inside a large mouthlike eyelid.

It feeds off raw energy without directly interfacing with wires or equipment and has only been seen drawn to sources of energy from abandoned ships, such as the Wrecked Ship and BOTTLE SHIP. The specter also taps into Mother Brain's "vicious brainwaves," meaning that Mother Brain may have some control over it, or that Phantoon simply feeds off of her energy. Nevertheless, based on its portrayal among the bosses in the Golden Statues, Phantoon is a high-ranked Space Pirate.

Background
Phantoon's origin has received alterations from several sources over the years. The English and Japanese manuals for Super Metroid both gave a different background of Phantoon, describing it as either being the ghost of the Wrecked Ship itself that taps into Mother Brain's thought-waves or as being the physical manifestation of Mother Brain's malevolent consciousness, respectively.

Another version of Phantoon's background is given in its concept art for Other M, which describes it as an entity who was hidden within a vessel used by the Chozo long ago - it apparently traveled with the ancient race through space for an unknown amount of time until they reached planet Zebes, where the vessel would eventually become the Wrecked Ship. The same concept art further describes Phantoon as a multidimensional creature whose entire body cannot exist in a single dimension, thus giving it its ghost-like characteristics. This signifies that the body that Samus sees as Phantoon in both games is but a portion of its overall structure, in which its full size, mass and appearance remain unknown. .

Super Metroid
"The Wrecked Ship has been shut down by the floating ghost, Phantoon." It absorbs the power from everything throughout the ship, including the internal power of Work Robots, leaving everything dark and inoperable, in order to feed its strength and gluttony. On top of that, its presence appears to bring out the souls of those who died in the crash, converging together and becoming evil spirits known as Coverns.

Shortly after Samus enters its room, several flames will ignite, floating in the center of the room. They will form a circle and start rotating around before closing in on each other. As they fade away, Phantoon begins to materialize to battle Samus.

Battle
Phantoon has two attacks; the creation of phantom eyes and ramming against Samus. It uses these two attacks in conjunction with its two abilities; becoming intangible and invisible.

It uses its phantom eyes in two ways: shedding a few from its mouth like tears that bounce along the ground, and creating waves of different patterns (circular burst, stalagtite style, crescent). However, Flame Attacks can either be destroyed for ammunition, or simply jumped through using the Charge Attack, making even the faster phantom eyes easy to dodge. It is possible for them to drop energy or ammunition.

Phantoon's first ability, intangibility, will be the entire theme of his fight. With its eye closed, it detaches itself from the physical realm, and only when its eye is open can Phantoon be hurt. Whenever the creature gains a physical presence, it can harm Samus on contact. It will float around with intangibility, and drop phantom eyes that bounce along the ground. When Phantoon finally opens its eye, it will create a circular wave of phantom eyes. It may return to this pattern, or suddenly vanish from sight.

Its invisibility is used often as well. After opening its eye, it will disappear, damaged or not. It may either float around while invisible to spawn bouncing phantom eyes, or suddenly appear with its eye open and create a wave of phantom eyes. While unnecessary, Phantoon can be tracked with the X-Ray Scope.

When damaged by Missiles or a charged shot from the Ice Beam, Phantoon will behave normally. However, disabling the Ice Beam will not make the ghost disappear, but instead return to floating around erratically with its eye wide open and its gaze locked on Samus, attempting to ram her. On the opposite spectrum, Super Missiles will send Phantoon into a fury. It will vanish, and reappear at the top of the screen and remain intangible for eight crescent waves of phantom eyes at very high speeds. These waves can be dodged by Samus in many different manners: by using the previously mentioned Charge Attack, by using the Morph Ball and sticking to the bottom corners of the room, though she'll need to be switching from left to right with each corresponding wave, or by jumping forward or backward in the middle of the eyes. Samus can also Wall-Jump over the crescents, or shoot the components separately to avoid damage.

As Phantoon takes more and more damage, its color will gradually shift from green to a hot red-orange. Upon its defeat, its eye will remain looking in the same direction as it begins to fade in and out rapidly, before a series of small explosions erupt across its body. Finally, Phantoon will begin waving around like its entrance, except wider and more violent until it stretches across the entire screen and dissipates.

With Phantoon's presence no longer dominating the energy crystals, power immediately returns to the ship. Lights turn on, both map and save stations begin working, conveyor belts start moving, Metal Doors release, Work Robots return to life, and severed wires start sparking dangerously.

Coverns also vanish from the Wrecked Ship, either from the light, or from being freed of Phantoon's malevolent control. However, the return of the craft's energy releases a variety of creatures that were seemingly dormant or locked away in the ship.

Finally, once the doors became unlocked, water from the lakes surrounding the crashed vessel flooded several rooms inside.

Metroid: Other M
Phantoon returns as the final boss of Metroid: Other M. No explanation is given for its reappearance.

When Samus returns to the BOTTLE SHIP, and reaches the ascent to the Control Bridge, enemies will begin to spawn from dark, swirling vortices to hamper her progress. These vortices are created by Phantoon, who has assumed control of the creatures of the BOTTLE SHIP, and has its eye set on revenge against Samus.

As she finally enters the Control Bridge, a massive tentacle suddenly smashes against the reinforced glass, and smashes into it again, creating thousands of cracks throughout one spot, and breaking off an overhead screen from its support. A gigantic bulbous head rises into view, pulsating visibly and audibly. Its double jawlike eyelid opens, and a piercing red eye leers at Samus.

Battle
Phantoon wastes no time in raising its bottom half and releasing more dark vortices, summoning its Rage Hands to deal with Samus. It will continue to wail onto the cracked window panes with both tentacles, and summon more in between until it finally smashes through. Alarms start sounding off, and oxygen is violently drained from the room, but Samus remains unaffected, her Gravity Feature keeping her feet steady.

Phantoon now attempts to defeat Samus with its improved phantom eyes. Still like blue eyes in a spiritual flame, they spread minimally and now focus on homing directly in on Samus. While these and Rage Hands distract her, Phantoon moves left to right, tearing more window panes open with its massive jaws.

After the top three window panes are shattered, Phantoon's eye becomes obscured by one of his swirling vortices, only to suddenly peak through it for a moment by extending its eye out on a prehensile eyestalk. It hides its eye again, and reaches right, smashing through the lower windows with its tentacle, and then repeats the same for the left side. The vortex hiding Phantoon's eye fades, and it unveils the rest of its attacks.

With the windows completely gone, Phantoon sweeps one of its tentacles at a time across the floor in an attempt to hit Samus aside. It will also begin spawning swirling red vortices on the ground that when stepped in, will burst into a pillar of agony. Finally, it will now shoot lasers from its pupil towards Samus in short bursts with little motion. When Phantoon becomes weak enough, its eye will collapse into the room and become primed for a Lethal Strike, though it is possible that this doesn't happen at all. By performing Lethal Strike, Samus will grab onto its eye and hold on as she's flung around on it, until she finally blasts the eye with a Charge Beam. She jumps off, and Phantoon floats away into space before bursting in a piercing white light and a loud bang.

However, if the Lethal Strike isn't performed, Phantoon will begin to lose control, smashing its own eye into the floor over and over, until holding it up and simply bursting into an orange goo. Phantoon will float away still, but without its eye.

Either way, a Grapple Point floats into the room so Samus can leave.

Powers and abilities
As befits a ghost, Phantoon has the power to turn intangible to avoid attacks, which is done by closing its eye. It can also turn invisible to elude opponents. Offensively, Phantoon has several powers to fight, powers that have been augmented in Other M. Its signature move is to create Phantom Eyes, ghostly eyes shrouded in a blue flame. Phantoon can also create Rage Hands; floating, disembodied hands that serve as extensions of its conciousness and are used to physically attack opponents. Phantoon can create large vortices of dark energy to damage Samus if she walked too close to them, and can use said vortices to teleport the bioweapons to fight her. Phantoon seemingly has the ability to control bioforms, as it was able to turn the BOTTLE SHIP's bioweapons against Samus in the postgame events.

Super Smash Bros. for Wii U trophy
"Samus originally faced this life-form in Super Metroid, but it appears again as a secret boss in Metroid: Other M after finishing the main story. Although the mysterious ethereal creature can only materialize its head in the physical world, its true form is said to be that of a giant."

Trivia

 * Sound effects still play regularly during the open-space portion of the Phantoon fight in Other M, despite the fact that this is impossible in real-life. This is consistent with other instances in the series when sound still travels in the vacuum of space, such as the Exterior Docking Hangar and Docking Bays.
 * Concept art from Other M depicts Phantoon as the head atop a vaporous humanoid body, with two larger Rage Hands as its hands. It also depicts Phantoon in its Super Metroid appearance despite it having a different design in the game, as well as a smaller size. Samus is also seen in the artwork battling Phantoon in the same manner as Andross from Star Fox.
 * Strangely, Phantoon in Other M uses one of its portals to bring out its eye, even though the eye is clearly attached to the eyestalk connected to the body.
 * In Other M, if Samus finishes off Phantoon with a Power Bomb, its eye will be colored red.
 * Although it might seem like Samus performs an Overblast on Phantoon rather than a Lethal Strike, this is not the case. She must fire manually, otherwise Phantoon may eventually push her off, but the move is activated by running towards the eye and holding the 1 button on the Wii Remote - the way to activate a Lethal Strike. To perform an Overblast, Samus must actually jump on to the enemy, which she does not do in this case.
 * Phantoon cannot be fought on Other M 's Hard Mode, as the game ends after the MB battle.
 * Phantoon in its Other M appearance is one of the largest bosses Samus has encountered.
 * Phantoon's physical structure is heavily similar to the Powamps from Maridia, but any connection between them is unknown.
 * Phantoon's eye in Other M greatly resembles the Eye of Sauron from Lord of the Rings.
 * Phantoon is, in a number of ways, similar to the boss Bellum from The Legend of Zelda: The Phantom Hourglass - among other things, both creatures possess an eye surrounded by teeth.
 * Phantoon's roar is nearly identical to that of Titanosaurus, a monster from the Godzilla franchise.