Queen Metroid

The Queen Metroid is the largest and most powerful Metroid featured in Metroid II: Return of Samus, serving as the final boss of the game. A Queen Metroid also appears in Metroid: Other M and Samus battles it near the end of the game.

Biology
She is best compared in structure to a crocodile; the creature has a quadrupedal posture with a large broad jawline containing three rows of teeth. The creature also has eight eyes in total, (two groups of four) and an extendable neck used for attacking with her impressive mandibles. Visually, the creature's features do not differ from the Omega Metroid's in any major way; only a few aspects change, such as the mouth and spinal plating. Similar to the other Metroid forms, her weak spots are her head and mouth structure as well as her stomach, the latter which can be destroyed either by one Power Bomb or some regular Bombs. However, her quadrupedal state also prevents external attacks on her stomach, requiring her to be destroyed from within. The Queen Metroid was the one responsible for reproducing the entire species, much like a "Queen" of an insect colony. Only very few Metroids are born with the specified genetic coding to eventually mutate into a Queen, again, much as an insect colony.

SR388
This creature thrived in the deepest confines of the entire cavern complex of SR388, in a ruined royal palace. This was the final Metroid that Samus Aran destroyed on her mission to the planet, but she took the Metroid Hatchling with her as she left.

Bottle Ship
During the events of Metroid: Other M, Metroids were cloned from fragments of the Baby on Samus' Power Suit and propagated in Sector Zero of the Bottle Ship. The first propagated Metroid matured to a Queen, something the scientists never predicted. She seems to be the organism responsible for the demise of Ridley's clone.

The Queen Metroid was stored within Room MW. When Samus tries to contact Madeline Bergman, she panics, and hits a button which opens a chamber. When Samus investigates, she sees Metroid Eggs, and learns that it would be none other than a Metroid Queen laying them.

During the battle, the Queen seems nearly impossible to defeat. Samus remembers the tragic deaths of Adam and Anthony and refuses to give up. She then loads Concentration and prepares to fire at the charging Queen, before the ship's emergency brakes throw them onto the ground. Samus takes the opportunity to shoot directly at the Queen's unprotected membrane (seemingly hitting its nuclei) and quickly enters the creature's body through its throat before laying a Power Bomb to obliterate her.

Madeline later explains that MB was the one who developed the first propagated Metroid into this beast, which treated her like its mother. They left the Queen's genetics unaltered, so she would act as a control group and produce unaltered Metroids for use.

It is revealed that Anthony Higgs hit the brakes on the Bottle Ship, thus, saving Samus' life from the Queen.

Metroid II
The Queen Metroid, as stated, is the queen of the species and her destruction in Metroid II halts the reproduction of the Metroids. Destroying the Queen requires at least 150 Missiles. Upon Samus's arrival, the Queen will immediately attack with her huge mandibles, which can be dodged simply by a well-timed jump. When the Queen opens her mouth to attack, she can be briefly stunned in place with a Missile, leaving her open for more attacks. The Queen will also periodically launch unknown globs from her mouth that track Samus, though they can be destroyed with a Screw Attack. As the Queen gets more damaged, her speed lunge speed increases, not giving enough time for Samus to leap out of the way.



There is also a more efficient way to destroy the Queen. After stunning the Queen with a Missile, Samus can instead go into Morph Ball form and enter her mouth, then roll into her stomach and plant Bombs (Samus will constantly be drained by the Queen while inside both maw and stomach, so she cannot delay). These will severely damage the Queen and Samus will be spat back out. The Bombs can also be used while inside the mouth, but does considerably less damage. It only takes about ten attacks of this method to destroy the Queen.

Should Samus become low on Energy, there is a small passage below the Queen that leads out of the nest. It can be used as an emergency escape route, though the Queen will have healed all damage when Samus returns. The escape takes Samus back to the room containing the destroyed Chozo Statue.

Once the Queen is destroyed, she falls to the ground, her corpse disintegrating while Samus' Energy is somehow fully restored. The Queen dead, Samus has access to the last Metroid Egg and her Starship.

Metroid: Other M
The Queen Metroid spawns three waves of Mature Metroids, first releasing one, then two, then finally three, each wave growing more resistant to the Ice Beam. The Metroids must be destroyed with the classic tactic of freezing and shattering them. If Samus stalls to kill one of the waves, the Queen will quickly produce the next one, and eventually all six Metroids will come into play. When any number of Metroids are frozen, the Queen will almost immediately attempt to free them by causing a tiny earthquake.

After all six Metroids are defeated, the Queen grows bright purple crystals on her neck and begins charging at Samus and breathing fire. These crystals can be damaged with a charged Super Missile, the Seeker Missile, and the Plasma Beam. After the ship's emergency brakes activate, Samus and the Queen Metroid are both thrown against the floor of the Bottle Ship. As the Queen attempts to get up, Samus can fire at the Metroid's belly, who momentarily gets back up and starts charging an extremely powerful variant of her fire breath. During this event, Samus grapples into the Queen's mouth, down her esophagus, and into the Queen's membrane. Samus then allows herself the use of Power Bombs and performs the secret method of killing the Queen from Metroid II, by laying one of her Power Bombs in the stomach, which causes a massive explosion that instantly kills the Queen.

If Samus fails to shoot the stomach before the Queen gets up, she will lunge her head and bite, killing her instantly. If Samus fails to grapple the Queen while she charges her fire, she will burn Samus and kill her instantly as well. The Queen will be constantly absorbing Samus's energy while she's inside it, as in Metroid II, so she must be quick with the Power Bomb.

Nintendo Power issue 31
"The leader of the Metroid mutations is a powerful creature with strong armor. You may not have enough Missiles to destroy it."

Metroid: Other M hologram information
"Common name: Queen Metroid  Size: Height 6m / Length 11m  Classification: Final evolution of Metroid with an ovisac."

Trivia

 * The Queen Metroid is one of the four known types of Metroids capable of spawning other Metroids, the other three types being Fission Metroids, Metroid Hatchers, and the Metroid Prime. The Queen Metroid is also the only Metroid capable of reproducing to not be mutated by Phazon in any way.
 * As the mother of all Metroids on SR388, it is quite possible the Queen in Return of Samus was the first Metroid ever created by the Chozo.
 * Curiously, there are an incredible amount of Metroid Eggs (albeit saturated with Phazon) on the planet Phaaze along with Metroid hives from which Phazon Metroids constantly spawn. Whether or not there was an egg-laying Metroid on the mentioned planet which served as a queen is unknown.
 * It is possible that a Queen Metroid goes along its own metamorphic path from Larva to Queen status. This is supported by the fact that the computerized Adam Malkovich makes no mention of the Queen when talking about the secret breeding program on the Biologic Space Laboratories research station in Metroid Fusion and speeding up the growth cycles of Metroids. He only talks about advancing a Larva to an Omega in a matter of days. However, Adam may have meant that the Federation had no intention of producing a Queen, since she would have started producing her own Metroids other than the ones created through cloning (which might have complicated matters). This is supported in Other M where Samus states that only special infants have the genetic coding to become Queens.
 * In the Restricted Lab, numerous tubes (presumably containing more Metroids) can be seen extending into the background of the Restricted Lab. It is unknown if the Federation actually did produce a Queen (that was not seen in game despite Adam failing to mention anything of it) and gave birth to all specimens.
 * This is also supported in Other M as well, since MB somehow bred an Infant to a Queen, seemingly without the use of replicating SR388's environment (thus increasing the chances of the BSL scientists creating their own Queen through SRX). Also, Madeline Bergman said they had no expectations of a Queen being produced so quickly. Samus also states that only special infants have the genetic coding to become Queens.
 * Because of this, it was implied that Baby, the genetic source material for all Metroids in question, was capable of becoming a Queen Metroid. If multiple specimens in the BSL Station were created through cloning, then they all had the potential of growing into Queens.


 * It would appear that Metroids which have the potential to become Queens grow much larger than typical Metroids before progressing to the next evolutionary stage. For example, the Baby grew to a massive size in its infant stage and the Omega Metroid cloned from the Baby also grew much larger than other Omegas previously encountered.
 * As the Metroid series is known to have taken inspiration from the Alien film series, it is entirely possible that the Queen Metroid was inspired by the Queen Alien from those films. Both Aliens and Metroid II: Return of Samus depict a final battle between the queens and the female protagonist (Ellen Ripley in Aliens and Samus in Return of Samus).
 * The scene where the creature emerges through blast doors is similar to the appearance of the Queen Xenomorph after being able to operate a lift near the end of Aliens.
 * It is possible that the first Queen Metroid knew of Samus' presence on SR388 and the fact that she was killing the Metroids. If true, the Queen may have been protecting the last Metroid Egg from Samus in case she intended to kill it. In fact, the Queen from Other M is shown to be very protective of its young during the battle, as it pounds the ground regularly in an attempt to shatter the ice encasing any Metroid.
 * During the fight with the Queen in Metroid II, there is a strange bar on the right wall that increases when the Queen's head nears Samus, and decreases when her head retracts. It is most likely a glitch that reacts to the Queen's sprite animations.
 * The Queen Metroid's "hurt" sound effect is the same as an Omega Metroid's in Metroid II.
 * The Queen in Other M does not retain any of her attacks from the original encounter in Metroid II and instead gains new abilities, such as growing crystals on her neck. It is likely that the fire-breathing replaced the shrapnel, however. It should also be noted that her artwork depicts her extending her neck, indicating that it was considered by the developers to be implemented. It is also possible that her head lunge replaces her actually extending her head. These differences may also be attributed to the Queen being exposed to stimuli that are different from those of SR388 (as seen with other Metroids throughout the series).
 * The Queen can seemingly create Metroids in two different manners: one involves the "normal" egg-laying method (with Infant Metroids eventually hatching from the eggs) and the other is giving birth to live Metroids (similar to mammals), as seen during the battle in Other M. With the latter method, the infant stage of a Metroid's life cycle can be skipped over, and the mature Larval Metroids "hatch" out of their mother's back, making openings on her spinal plating as fluids burst out; this seems to be a defense mechanism.
 * However, it is possible that the Queen is capable of storing Metroids in her back for protection and/or nursing. This explains how the Eggs were present with no living infant/adult stages nearby. The concept art of the Queen portray Metroids submerged in the Queen's back, but unlike the ingame depiction, the Metroids are merely attached to her and not encased inside her spinal plating.
 * Queen Metroids have two tube-like appendages on their rear. Their purposes are unknown, though they are potentially the organs responsible for laying Metroid Eggs (as there is a lack of any other protrusion on the Queen's body that could serve this purpose). Curiously, each time the Queen from Other M rams against a wall, the impact causes green fluid to squirt out of the two tube-like structures.
 * It is seen in Other M that the Queen's vision is blurred pink. This is seen in the cutscene where she kills Ridley and when approaching Samus. Also, an extremely faint greenish glow can be seen around Ridley and Samus during these same cutscenes. This may suggest that the Metroids, or at least the Queen, can sense their prey's life force.
 * There is a slight inconsistency with the gender of the Queen in Other M. Samus calls the Queen female except when she says that "...The newly hatched infant took to her like his mother."