Metroid franchise strategy guide/Creatures in Metroid Fusion and Metroid: Zero Mission

This is a list of creatures in the Metroid series games Metroid Fusion and Metroid: Zero Mission made by Nintendo.

X Parasite
The X Parasites (or just the X) are the main villian of Metroid Fusion. In their natural form, the average X Parasite is a hovering, volleyball-sized amoeboid creature that glows yellow, green, or red. A mutated blue variety also exists. Sometimes several such parasites will combine into a larger, more powerful form, known as a Core-X. The X Parasite mutates easily in order to adapt to new environments. X Parasites have the unique ability to infect, copy the DNA of, and kill another creature, then use the stolen DNA to create a new body with the same form and behavior as the previous host. Whereas normal X Parasites can only imitate weaker hosts, Core-X can also imitate much stronger ones. The X are also capable of combining DNA from various hosts to create a new creature with the abilities of the individual host forms. The X Parasites can also download and process electronic data organically. When threatened, an X Parasite will revert to its amoeboid form and is extremely difficult to harm, except by attack from a Metroid. X Parasites reproduce by asexual division.

Strictly speaking, the X are parasitoids (endoparasitoids to be exact) rather than parasites. In a parasitic relationship, the host is not generally killed, whereas in a parasitoid relationship, the host is usually killed after the full development of the other organism, which is the case with the X.

One of the startling revelations in Metroid Fusion is the apparent intelligence of the X. Although first believed to be merely instinct driven mindless organisms, the X exhibit remarkable adaptation and even plot various traps to defeat Samus. Either by duplicating sentience or intelligence from the host bodies they infected, or having always been intelligent, by the time of the game they have achieved intelligence at least of human level. The X, realizing Samus' new vulnerability to cold, actually mutate some parasites to be cold so that if Samus absorbs them or even touches them, she'll be severely hurt. A suit upgrade defends Samus from this problem, however the X also has the SA-X attempt many different ambushes in order to kill Samus. The X also mimic the dead corpse of a researcher in order to gain access to a particular computer terminal for their own purposes. The X even animated the dead corpse of Samus' longtime nemesis Ridley in order to exterminate her. When it is revealed that Federation Ships are on their way to retrieve the X, Samus knows that they will be no match for the X and will be used by the parasites to infect the entire universe. Indeed as Samus' A.I. companion Adam states, the intelligence of the X is nothing short of remarkable...and a little terrifying.

The X Parasites are such prolific breeders that on their home planet of SR388 they threatened to destroy the ecosystem. The Chozo stepped in and created the Metroids in order to keep the X Parasites' numbers in check. When series protagonist Samus Aran exterminated all of the Metroids on SR 388 in Metroid II, the X Parasites' population quickly made a comeback. They provided the main antagonist role in Metroid Fusion, particularly in the form of the SA-X, an X mimic of Samus Aran and her Power Suit. As the X continued to menace the station, the Federation took an interest in the X. They ordered Samus' computer to confine her until Federation ships arrive. Samus, knowing that the X would overwhelm them and spread through the universe, set the station on a collision course with SR-388. By doing so, all of the X on the station and the planet would be destroyed. The SA-X tried to stop her, but was defeated. It should be noted, though, that the SA-X comes into the melee between Samus and the Omega Metroid, and attempts to kill the creature (unsuccessfully). Samus absorbs the SA-X and defeats the Metroid, then escapes the doomed station. Whether the SA-X was attempting to save Samus or just kill the Omega Metroid is a mystery. However, seeing as the Metroids are the X Parasites natural enemy, and both Samus and the Omega Metroid had Metroid DNA, it is likely that the SA-X was simply trying to neutralize the greater threat (the Omega Metroid) first.

B.O.X.
A rogue security robot Samus enconters fairly early in her mission. At first it is not infected by the X and attacks Samus by charging at her and shooting fire column producing bombs from its core. As the battle goes on, its core wears away to reveal a 'brain' inside before it escapes. Much later in the game, its organic parts become infected by the X that contains her Wave Beam data, which takes over the machine, and it can then electrify the water (possibly with the Wave Beam's energy or damage to it's circuity), jump higher, and fire homing missiles at Samus. Defeating it (and its Core X) returns the Wave Beam to Samus, allowing her beams to pierce walls.

Yakuza-X
An insect that shows up when Samus attempts to go restore the auxiliary power to the station. Yakuza's first form consists of it moving up and down the metal wall in the background, attempting to either grab Samus or bombard her with fireballs. After Samus destroys the legs it uses to latch to the wall, Yakuza-X uses the Space Jump to spin around wildly and spit debris at Samus. After being destroyed, it becomes a Core-X that, after destroyed, will leave Samus with the Space Jump, allowing her to infinitely spin in mid-air and basically fly. (Contrary to popular belief, Yakuza-X is not an arachnid because it has 6 legs rather than 8.)

Drip Lizard
In certain narrow shafts above (or below) Samus, large reptilians move about, spitting out globules of acid that fall straight down. The lizards are slow moving and require only minimal effort to kill, but the presence of the shaft's floor means only the Power Bomb and Wave Beam can reach the nuisances. They are found traveling in rather large groups in all their appearances. They have a resemblance to the Xenomorph species from the Alien series, and, like the alien, crawl around in the roof.

Fake Energy Tank and Missile Expansion
These beings resemble Energy Tanks or Missile Expansions until Samus gets close to them; then, they spread bat-like wings, reveal a set of eyes and fly off, hurting Samus. They are the result of an X-Parasite intelligently mimicking an Energy Tank or Missile Expansion with the intent of catching Samus with her guard down. Careful exploration after an encounter with one of these enemies will reveal a real Energy Tank or Missile Expansion, usually in a sealed-off area.

Mermen Pirates
The result of an X containing fish DNA combining with an X containing Space Pirate DNA. The result is a swimming Pirate with a tail instead of legs. Mermen Pirates fire short, red blasts and swim towards Samus at rapid speed. This makes them better suited to water than normal Space Pirates, whose standard long greenish-yellowish beams move slowly in water, and who are hindered by the presence of the liquid.

Nightmare
Nightmare is a biomechanical organism engineered in the Biologic Space Laboratories to be an unstoppable weapon. It appears as a X-clone boss in Metroid Fusion, in the ARC sector. The Nightmare has an integrated gravity field generator which causes Samus to lose movement speed and missiles to fall to the ground before reaching their target. It also distorts light waves in the process. The Nightmare utilizes six rayguns, as well as being given heavy shielding by its creators. Its 'eyes' sometimes drip green slime if it is shot enough in the right place. If Nightmare is damaged enough, its field generator is destroyed, and its mask falls off to reveal its true face, which is covered in green slime. It also has six eyes even though the mask has only 2 openings. When the Nightmare is defeated Samus retrieves the Gravity Suit, allowing her to move in water without resistance.

Serris
An aquatic serpent-/dragon-like animal. It has the ability to swim at incredible speed. It is kept in the AQA sector of the Biologic Space Labs. After the X-Parasites infested the BSL, Serris was killed and copied by a Core-X. While fighting Serris, the ladder on the ceiling can be used as a "safe spot", where players can wait for the creature to jump up to the leap out of the water and shoot its head. Upon its defeat, Samus receives the Speed Booster. In a room seen before fighting Serris players can see the original creature's remains. The skeleton is completely stretched out, this may indicate that the X killed it quickly not giving it time to squirm around. However, the remains of Serris are smaller and in a slightly different shape than the Serris that Samus must fight. This may mean that it had shed its skin recently, but it is unknown.

Zombie Researcher
The result of an X Parasite that has combined a slime organism and a human's DNA. These beings appear in a few rooms of the Main Deck, and have the lowest stamina of any enemy; a single shot from Samus' unaltered beam can kill them. They can be revived, however; unabsorbable X will often reanimate the pool of sludge (which, on a strange side note, can seemingly drag itself around) they leave on the ground after death. Samus may have become something such as this if her X Parasite infection was left untreated.

Golden Pirate
The result of highly evolved X mimicking a pirate. Only two ways exist to defeat them. The first is hitting it from behind with a fully charged beam or a Missile. The second is using the Screw Attack.

Pirate
An X mimicking a Space Pirate. They can hang onto walls and jump between them, and can attack from a distance using a sort of wave beam they shoot from their claws. They can also chase (by running after her) and attempt to shoot Samus and use their amazing jumping ability to try to reach her if she tries to jump or 'fly' to safety, but the Pirates (in Fusion) can never do both; Pirates that cling to walls stay on the walls, and grounded Pirates can only jump at Samus. They come in three forms.
 * Regular
 * Merman
 * Golden

Nettori
The Plasma Beam Core-X, otherwise known as the Nettori, takes the form of a large statue covered in vines. It resembles a Chozo statue from Zero Mission wrapped in vines. There are two flowers on the top of the screen, and three on the bottom. Any contact with the boss will result in damage, though some of the flowers will release small pollen-like projectiles that can do a little damage. They knock Samus back and often send her into the lower set of flowers which behave in a leech-like way, trapping Samus and draining her energy and holding tighter if she struggles. At first, the Nettori does nothing, and Samus can shoot the central body of the plant to damage it, but the two flowers on the ceiling will continually produce pollen to distract her. For the second part, Samus must dodge the beams that are fired from the main plant and continue to attack it with either the Charge Beam or Missiles. The destruction of the second stage X will reveal an Eye Core-X. Destroying that will award Samus with the Plasma Beam. Unlike in Super Metroid, the Plasma Beam is fully compatible with the Wide Beam, and represents a very large power increase for Samus.

SA-X
The SA-X was an X-Parasite clone of Samus Aran, created when one of the parasites infected Samus Aran, and the biological portions of her Power Suit, while she was on planet SR388. During the medical procedures required to save Samus' life, the infected portions of her suit were surgically removed.

The infected Power Suit pieces were transported to a B.S.L. Research Station in orbit above SR388. The parasite within the suit recreated Samus Aran's body using the DNA it had absorbed, and promptly escaped its containment cell using one of Samus' Power Bombs and set free all the X Parasites in the Quarantine Bay. Samus was sent to the station to find all crew members dead and the X infesting several sections of the station. Her initial investigations accidentally allowed the X access to some of the breeding environments by releasing security locks. Subsequently, the SA-X manipulated Samus by destroying doors and wreaking havoc in certain areas to release all the security locks and allow the X Parasites access to all breeding areas.

During the course of the game, Samus discovers a secret laboratory on the station that is cultivating Metroids, which the SA-X ravages (and is promptly devoured by several Metroids). After the lab is detached from the station with the SA-X on board, Adam, Samus' computerized CO, explains that the SA-X has been reproducing and that now there are no fewer than twelve SA-X onboard.

The SA-X is extremely dangerous in close combat, mimicking Samus at the height of her powers. It is equipped with the Screw Attack and Space Jump, and fires beam shots appearing to be a combination of the Plasma, Ice, and Wave Beams. It will also fire super missiles at Samus, but this rarely occurs since the SA-X prefers the Ice beam weapon. It cannot be damaged by Samus until the final fight against the SA-X.

Samus prevails over another SA-X in close combat, which morphed into a large monster after several Charge Beam shots. After the SA-X physical, monster, and Eye Core-X forms are defeated, the parasitic SA-X escapes before Samus can absorb it (as she did other X Parasites). This SA-X resurfaces a short time later, after Samus had set the B.S.L. station on a collision course, during Samus' final battle with the Omega Metroid, when Samus is about to be killed. The SA-X fends off the Omega Metroid but is then fatally wounded, returning it to its parasitic state. (Some suggest that the SA-X came back and fought the Omega Metroid because the X parasites were natural enemies of Metroids, with this reasoning demonstrated by how the SA-X desired to destroy the cultivated Metroids of the base. Another theory is that knowing Samus had set the station to explode on SR388, the X determined that only way for them to survive was to commandeer Samus' ship and escape.  A third theory is that she attacked the Omega Metroid because she saw it as the biggest threat, applying the "enemy of my enemy is my friend" rule.)

It is then absorbed by Samus, which fused her original power with her new Fusion Suit abilities and completes her. This new suit, nicknamed the "Omega Suit" (which it is not actually called such in Metroid Fusion) finally gives back Samus's Ice Beam. Using her newly restored power, she defeats the Omega Metroid using the Ice Beam and clears the way. Adam, with the help of the Etecoons and Dachoras, pilot Samus' ship to pick her up before the station crashes into SR388, eliminating most, if not all, the X Parasites on it (most likely including the last ten SA-X).

Acid Worm
A long, tentacle-like creature that appears in Kraid's Lair after activating the ziplines. It appears from a shallow pool of acid and attacks by shoving its entire upper body out of the acid, while leaving some of itself still submerged to serve as an anchor. Samus must wait for it to wiggle its tentacles (the sign it will attack) and ride the zipline in the room to another platform. The worm gets stuck in the block Samus was standing on, exposing a weak exoskeletal joint that is highly vulnerable to Missiles. However, damage can be dealt via Charge Beam.

Bio Barrier
The Bio Barrier is a living blockade- a large smooth sphere suspended in the air by veinlike appendages. It will not attack players and cannot be defeated by any of Samus' weapons. The only way to destroy it is to carry the small parasites, called Blootiks, who attach to Samus, to it. When she approaches a Bio Barrier with Blootiks on her, they will leap off and quickly eat away at the Barrier. It should be noted that unless Samus has the Varia Suit, these bugs will damage her as well if there are at least four on her.

Blootik
Tiny parasites who attach to Samus if she touches them, but do not do any damage to her unless there are many attached to her at once. The Varia Suit seems to nullify this damage. They disappear if the Morph Ball Bomb is used or if Samus walks to another room. The Blootiks can be used to destroy Bio Barriers by eating them.

Charge Beam Worm
This spiny worm of incredible size appears at different points in the Brinstar region until Samus defeats it or it appears five times. It uses its long body to box in Samus, then shoves its head at her. Upon returning the head to the ceiling, it opens its eye to find Samus. The eye can be damaged during this time. As the name suggests, killing the creature gives Samus the Charge Beam.

Imago
A giant bee-like organism who is originally fought in its cocoon, but is later fought inside a cave to obtain the 'first' Super Missile pack. As a cocoon, the player must use the Winged Ripper to jump up and hit the "vines" holding it up, making it crash through the floor. In its final form, the player must repeatedly hit Imago's stinger to kill it and cause it to destroy another wall and obtain the Super Missiles.

Mecha-Ridley
The final boss of Zero Mission, encountered deep inside the Space Pirate Mothership, is a massive robot that bears a striking resemblance to Ridley. It appears to be incomplete at the time of the battle, as it has no legs, and drags itself around by its arms. It attacks using its razor-sharp claws, lasers, a homing missile launcher, and can send a barrage of fireballs out, similar to the real Ridley. Notably, with the exception of a single panel on its chest, the machine is completely impervious to Samus' attacks. When Mecha-Ridley is destroyed, it, like the Mother Brain before it, triggers a self-destruct sequence within the Mothership.

Ruins Test (also called Warrior Shrine)
When Samus finally works her way through Chozodia and escapes the Space Pirates, she reaches a room that she once visited as a child. This room contains a massive painting of a Chozo warrior. This is not a typical "boss battle" but rather a Chozo-developed test of Samus' abilities. She then engages in battle with this painting; four emblems are present on the surrounding wall, and they are "absorbed" by the orb the warrior is holding. The orb will occasionally flash an emblem, and Samus must shoot the orb with a fully charged pistol shot during this brief period of time. When an emblem is not showing, the orb has a mirror image of Samus. If the orb is shot during this time, Samus damages herself. Passing the test requires shooting all four emblems (they return to their respective location on the wall after being shot once). When this happens, Samus' mirror image shows her wearing the new Power Suit, which she subsequently absorbs. She has thus earned her new Power Suit, and activated the three Unknown Items. In the cut-scene at the end of the game, it is revealed that she chipped a crude engraving of herself and her adoptive family into the painting as a child.

Eye-On
Eye-like creatures which emit a beam of light. If the beam is disrupted, they alert the Space Pirates of Samus' presence and begin shooting energy beams, but they can be destroyed simply by shooting them with the Plasma Beam; however, they are impervious to Samus' Stun Pistol. They can only be found in Chozodia.