Core-X are large X Parasites that have incorporated into themselves either an important ability from their victims or one of Samus's lost power-ups. They take the form of a boss and, upon defeat, discard the host body and reveal their natural form.
Core-X are surrounded by a tough shell covered in spikes. To break the shell, Samus has to fire Missiles at it. Once Samus has damaged it, the shell will flash for a few seconds, giving it temporary invincibility. As it takes more damage, it changes color from green to yellow to red. If Samus uses any Beam weapon on a Core-X or Screw Attacks it, Yellow and Green X Parasites will fly out of it; this may be a defense mechanism to launch the pure form of X so that it may infest whatever creature is attacking it. Since Samus is part-Metroid throughout most of the story's events, this defense mechanism becomes an advantage to her since she can absorb X to replenish her stamina and ammunition.
A Core-X was once a regular X Parasite, but it was able to find a host with such power that it gained a hard shell and the ability to produce more X. For example, a normal yellow X infected Samus, but a Core-X is revealed when the SA-X is defeated. The powerup that Samus recovers from a Core-X oftentimes belonged to the host it previously infected, and is used greatly by the parasite in its battle with Samus. For instance, Samus gets the Morph Ball from Arachnus, who rolls up into a ball, the Space Jump from Yakuza, whose head continuously jumps, the Gravity Suit from Nightmare, who controls gravity, the Speed Booster from Serris, who moves at incredible speeds, and the High Jump Boots from Zazabi-X, who leaps extremely high.
As the game's story develops, the computerized Adam Malkovich warns Samus about the X evolving and growing stronger to the point where some of them are becoming resistant to her weapons. This is evidenced by the increasing number of Missiles it takes to defeat each newly encountered Core-X, with the very first Core-X (Arachnus) only requiring three Missiles and the next Core-X (Zazabi) requiring four, needing an additional missile to change it from blue to yellow in color. It finally plateaus at six Missiles to defeat a single Core-X, which will take two missiles to change phase/color. (Note as well that by this point Samus has acquired the Super Missile upgrade, which triples the strength of each missile. Therefore, a Core-X at the end of the game that takes six Super Missiles to defeat actually possesses six times the durability of the first Core-X fought.)
Variants of the Core-XEdit
There are two types of Core-X. The simplest to defeat is the normal Core-X that moves at high speeds around the arena trying to tackle Samus with its spiny exterior. This Core-X simply requires Samus to shoot it with Missiles until the shell cracks off to allow the absorption of the X inside.
The second variant is one that holds a beam weapon, sometimes known as a Hard Core-X or Beam Core-X. This Core-X that has complete protection from any weapon, including Missiles. While this kind of Core-X moves at slower speeds than a standard Core-X, it is also equipped with a long-range attack. Because they hold beam upgrades for Samus, it's not surprising that the Core-X would try to use the beam's power, giving them the alternate designation Beam Core-X. In battle, the Core-X will open an eye-like part of its shell and begin charging an energy weapon, just as Samus would with her Charge Beam; each Core-X uses the weapon that it holds (for example, the Core-X that appears after the defeat of the SA-X uses the Ice Beam). The Core-X will then fire the beam after it is fully charged. The charging period is the only time that the Core-X is open for attack, and only the "eye" can be damaged. The beam will be fired prematurely if the Core-X is hit, so it is recommended that Samus jumps as soon as she fires a Missile.
List of creatures containing the first variantEdit
- Arachnus; Morph Ball
- Zazabi; High Jump Boots/Jumpball
- Serris; Speed Booster
- Barrier Core-X; Varia Suit
- Yakuza; Space Jump
- Nightmare; Gravity Suit
- Neo-Ridley; Screw Attack
List of creatures containing the second variantEdit
- Elephant Bird; Charge Beam
- Scientist; Wide Beam
- Nettori; Plasma Beam
- Security Robot B.O.X.; Wave Beam
- SA-X; Ice Beam and Unnamed Suit
- The SA-X's Core-X replenishes all weaponry and all Energy, while all others only restore 5 Energy Tanks, 50 Missiles, and 10 Power Bombs.
- Whenever a Core-X is hit by any of Samus' attacks, a smaller X-Parasite is formed and subsequently breaks away from its larger brethren, allowing Samus to slightly refuel her Energy or Missiles.
- If the Screw Attack is performed for long enough on a Core-X, it will cause a large amount of smaller X-Parasites to form, giving Samus a quick and easy way to completely restore her Energy and Missiles. However, this can only be done in the semifinal battle against the SA-X, seeing as how all the others have been absorbed by the time the Screw Attack is acquired.
- The form Metroid Prime takes upon being vanquished in Metroid Prime resembles that of a Core-X.
- The Core-X without its shell resembles an adenovirus, a type of virus with an icosahedral capsid structure.