There's a strong likelihood that the Metroid's mortal weakness, the vulnerability to cold, has been overcome through genetic manipulation. And if that's true, there's no way you can destroy them.

Commander Adam Malkovich

Unfreezable Metroid 2

An unfreezable Metroid in its tank. Note its unique coloration and spiked nuclei.

An unfreezable Metroid (also referred to as Sector Zero Metroids or Genetic Metroids) was a Metroid larva that was genetically manipulated to overcome the species' major vulnerability to cold temperatures in order to maximize its potential as a bioweapon.

In the first Metroid Prime game, according to the Pirate Data, Metroid Forces, the Space Pirates hoped to find a way in the future to shield Metroids from the cold, but are seemingly unsuccessful or they never gained the opportunity to attempt this.

Ironically, it would later be the Galactic Federation, the very enemy which the Space Pirates hoped to defeat with their Metroids that ultimately created unfreezable Metroids in a controlled environment.

Role Edit

In Metroid: Other M, the existence of the Federation's unfreezable Metroids are first alluded to when Samus Aran came across a dead Gigafraug within the BOTTLE SHIP's Cryosphere. The creature's body featured evidence of it's life energy drained by a Metroid, something that Samus commented as an impossibility due to Sector 2 being a sub-zero environment.

Later on, she would be informed that the ship's scientists successfully cloned Metroids from the deceased baby's organic matter preserved on Samus' Power Suit following the events of Super Metroid. All, but a few are genetically altered to be unfreezable and are stored in Sector Zero. These Metroids are part of a bioweapon program titled Project Metroid Warriors. If successful, they would have entirely replaced the Galactic Federation's modified Zebesian Pirate forces.

Unfreezable Metroid

Wireframe hologram of an unfreezable Metroid.

Later on, it was stated that the genes of the BOTTLE SHIP's Queen Metroid are left unaltered so it would act as a control specimen. She would give birth to normal Metroids to be used for further research and eventually changed into unfreezable specimens.

The physiological differences between the modified and natural Metroids are their nuclei and overall pigmentation: The unfreezable variant display spiked nuclei rather than the regular raspberry-like shape while the colors of it's skin and membrane are purple and blue instead of the common red and green, respectively.

After MB took over the BOTTLE SHIP, she intended to use them against the Galactic Federation HQ. When she encountered an unknowing Samus Aran, she posed as Madeline Bergman and revealed to her most of the data regarding Project Metroid Warriors and the location of Sector Zero, but withheld the crucial information regarding the unfreezable aspect of the Metroids. MB did so in the hopes that the specimens would have the element of surprise and kill the unwary Samus, but this plan was ultimately foiled by Adam Malkovich when he prevented entry to the area and warned her about the Metroids' modified genes.

The unfreezable Metroids were ultimately killed by Adam when he triggered Sector Zero's self-destruct mechanism.

Prior unfreezable MetroidsEdit

Before the events of Other M, Samus had encountered several strains of Metroid that were either impossible to immobilize in ice, or were invulnerable to damage from cold-based weapons. The first category is the later stages of a Metroid's life cycle on SR388: the Alpha, Gamma, Zeta, Omega and Queen forms. The exoskeletons and tissue of these older individuals prevented their bodies from being encased in ice, but their exposed membranes or mouths could still be harmed and/or partially frozen with the Ice Beam. A charged shot could freeze the membranes of Alpha and Gamma Metroids, but this didn't completely immobilize them.

The second category covers several of the Metroid mutants created through Phazon. These include the Fission Metroid, Metroid Prime and the Metroid Hatcher. Although the Space Pirates extensively experimented with Phazon, the marauding race played no role in the birth of the first two mutant strains, as they were created outside of Pirate laboratories and were therefore incapable of recreating them in a controlled environment. While the Metroid Hatcher could still be damaged with Ice Missiles but not frozen, the Fission Metroid and Metroid Prime could achieve complete invulnerability to cold-based weapons depending on a few factors. The Fission Metroid had a high probability of splitting into two Metroids that were immune to the Ice Beam, and the Metroid Prime's first form could briefly be damaged with said weapon and frozen with the Ice Spreader if its exoskeleton shifted to a white color.

Finally, the Giant Metroid Samus encounted in the similarly-named Super Metroid could not be harmed, immobilized or repelled with any of her weapons, including the Ice Beam and stacked/charged variants.

Hologram informationEdit

Common name: Genetic Metroid
Size: Length 1.5m
Classification: Metroid subspecies able to endure frigid temperatures.


  • Whether the Gigafraug's corpse in the Cryosphere of the BOTTLE SHIP implies that an unfreezable Metroid escaped Sector Zero, or was the result of an earlier test performed by the ship's scientists to verify the Metroid's invulnerability, remains unknown. It is interesting to note that a cutscene of a modified Metroid breaking its containment tank is shown during Adam's exposition on the organisms.
  • Despite being unfreezable, Adam was able to freeze and kill a baby Metroid that almost killed Samus. Adam infers that, due to its young age, its modified genes had not yet manifested.
  • While the modified Metroids from the BOTTLE SHIP could no longer be frozen, they may have retained their alternate weakness to Power Bombs.
    • This is made less likely by the fact that they are clones of a member of the Metroid strain from SR388, which does not have this alternate weakness.
    • Other M's Power Bombs may have possessed enough firepower to damage Sector Zero and activate its self-destruct procedure, thus killing all unfreezable Metroids. However, this would have consequentially led to Samus' death, as she would be required to detonate the Power Bomb(s) from within the sector, therefore trapping her inside when it would detach from the BOTTLE SHIP and explode.
  • The model for the unfreezable Metroid is present in the game's data, possibly indicating that a non-pre-rendered version of the cutscene featuring it was intended at some point.
  • After Samus receives Metroid DNA in Metroid Fusion, the Galactic Federation provides Samus with the Varia Suit upgrade which renders her immune to cold temperatures and prevents her from being frozen by the SA-X's Ice Beam, technically making her an unfreezable "Metroid".