This article refers to the natural infant life cycle stage of the Metroid. For the specific infant Metroid that imprinted onto Samus as its mother, see Baby. For the infant that Samus encounters in the BOTTLE SHIP, see Baby Metroid.

The Infant Metroid, also known as the Metroid Hatchling, is the second stage of a natural Metroid's life cycle. Upon hatching from its egg laid by a Queen Metroid, the infant's body consists of a transparent, green membrane that surrounds four minuscule red nuclei, and two pairs of tiny fangs on the underside. At first sight, Metroid Hatchlings appear to be harmless; in the presence of an unrelated organism, they will circle around it and observe with great curiosity. While this behavior leaves the Metroids in a highly vulnerable position, they can quickly become unpredictable and may strike without warning in order to devour their prey's life energy. After an undetermined amount of time, an infant will grow into its next and most commonly encountered stage in the species' life cycle: the Larva Metroid.

Contrary to the highly resilient larvae which requires a combination of freezing and concussive weapons to kill, Infant Metroids can die from a single shot fired from any cold-based weapon, shattering them on contact. Otherwise, they appear to be invulnerable to most weapons.

Metroid II: Return of Samus/Metroid: Samus ReturnsEdit


Metroid II: Return of Samus

Samus Aran would have a long history with the Metroid species and their many unnatural variations across several planets prior to encountering her first Metroid Hatchling during a mission to SR388, the species's homeworld. Despite being tasked with rendering the native Metroids extinct, Samus hesitated when she happened upon the very last Metroid left on the planet hatching from its egg in front of her. Never having come across a natural Infant before this moment, Samus was caught entirely off-guard by its confused, curious yet playful and childlike behavior, traits she had never seen in any Metroid she had killed throughout her life. Indeed, even the variants she encountered in the past that remotely resembled a hatchling in shape and size only were Infant Tallon Metroids and Miniroids, both of which were unnatural mutants exhibiting extremely aggressive and absolute indifferent behaviors, respectively. The native Infant quickly imprinted onto Samus as its mother and never attempted to attack her. It even assisted her in defeating Proteus Ridley, who had come to SR388 to capture the baby.

The design for the Infant Metroid varied between games based on the concept art for both games. In the original concept art in Metroid II: Return of Samus seen in the Metroid II concept gallery for Samus Returns, the Infant Metroid stage was overall similar to the Larval stage, only it had significantly less veins between its membrane and nuclei than the Larval stage, and only had two fangs. In Samus Returns, on the other hand, the Infant stage does have four fangs, albeit stubbled and extremely tiny especially in comparison to the Larval forms. In addition, in Samus Returns, the actual membrane is also colored light blue while the larval form is colored green.

Super MetroidEdit

The same Infant Metroid from the previous game is present on the Title Screen, in the introduction cutscene and in the Ceres Space Colony prologue. With the exception of the flashback showing the Infant's birth, the harmless organism is always seen within a small glass container with blue lids. After it is captured by Ridley and brought to Zebes, unknown factors caused it to mutate into the vicious giant Larval Metroid. Interesting to note is that the mutant could produce the exact same cries as an Infant after recognizing Samus.

Metroid: Other MEdit

When Samus reached the entrance to Sector Zero in the BOTTLE SHIP, she was surprised by a single Infant Metroid, presumably born from an egg laid by the Queen Metroid present in Room MW. She once more hesitated to attack it, remembering the Infant from SR388; this new hatchling demonstrated a similar peaceful nature. Just as Samus had resolved to kill it, she was attacked from behind by Adam Malkovich, leaving her defenseless on the ground. The Infant Metroid, who seconds earlier had shown no predatory behavior, made its intentions clear by stretching its fangs wide in order to feed on the weakened Samus. However, Adam killed it before it could lunge at her.

It is eventually revealed that corrupt factions of the Galactic Federation had attempted using an android carrying Mother Brain's artificial intelligence as a means to safely control the Metroids being created within the BOTTLE SHIP. This involved exposing newly-hatched Infant Metroids to the android with the hopes of recreating the bond that occurred between Samus and the hatchling from SR388, thus making the dangerous species submissive and loyal. It is never clarified what degree of success this method had with the Infants other than the bonds themselves had a significant impact on the android, possibly on an emotional level.

Metroid FusionEdit

The Infant from Metroid: Samus Returns and Super Metroid is referenced in the introduction cutscene. It is revealed that a medical team under the Galactic Federation utilized a preserved cell culture of the hatchling in order to create a vaccine capable of saving Samus' life from an X Parasite infection. After administering the serum, her DNA fused with the Infant's, making her invulnerable to future X Parasite infection; this event likely contributed to the discovery of Metroids being the natural predators of X.

Infant Metroid Fusion

Infant Metroids in the Restricted Laboratory.

Later on, Samus discovered the Restricted Laboratory in the Biologic Space Laboratories research station. This area was designed to produce and rapidly grow Metroids through every stage of their natural life cycle. A large quantity of Infants occupied the majority of the lab and were the only active specimens, as the other, more developed Metroids were seemingly kept in suspended animation. An X Parasite mimicking Samus quickly located the lab as well and wreaked havoc with its weapons, triggering the area's self-destruct countdown. While it seemingly managed to kill several Infants, its destruction broke every containment glass, freeing all remaining hatchlings. Eventually, a small group of Infant Metroids swarmed and overwhelmed the SA-X. As they fed on the writhing mimic, Samus climbed to the top of the lab where more Infant Metroids roamed freely in the air. Though they never showed hostility to Samus herself, their bodies acted as small obstacles that could unintentionally disrupt her Space Jumps. Interesting to note is that none of the weapons carried by Samus at this point in time are capable of harming the Infants, including the Ice Missiles and Power Bombs. Immediately after her escape, the Laboratory detached itself from the BSL and exploded after distancing itself, killing all Metroids inside. However, it was later discovered that a single Infant managed to escape the Laboratory prior to its detachment; the Metroid then devoured all X Parasites present in its path as it molted through its life cycle. Due to the modifications made to all Metroids onboard the BSL by its scientists (hinted at by the computerized Adam), it metamorphosed at an unnaturally high speed and quickly reached the Omega Metroid stage.

Other appearances in the seriesEdit

Metroid MangaEdit

Original Metroid
An Infant Metroid was present in Tourian during Old Bird's discussions with the rest of the Chozo prior to the Space Pirates' take over of planet Zebes. The manga insinuates this Infant is the first Metroid in existence.

Metroid Prime: Federation ForceEdit

Only a single Infant Metroid is featured in the game during the post-credits ending. This ending consists of a character resembling Sylux infiltrating a secured Galactic Federation room where a Metroid Egg is held inside. Acquired from a Space Pirate research site on the planet Talvania, the egg promptly hatches after the infiltrator uses a heated-beam on it. This Metroid hatchling has no visual differences from the artificially enlarged Larval Metroids seen earlier in the game, other than being smaller in size. This is due to the developers using the same model for both stages of the species' life cycle.


  • The events of Metroid: Other M imply that the relationship between Samus and the Infant of SR388 is a bond that can be feasibly achieved with other Metroids, requiring nothing more than placing an individual in front of a hatching egg. However, due to the fact that all non-Infant Metroids seen in the game were never present in the same room as the android, MB, the strength of their bond is left unknown, if there ever was.
  • Metroid Prime: Federation Force seems to further trivialize this bonding between Metroid hatchlings and non-related entities. There is a Space Pirate log titled "Imprinting" found in Talvania's research site which describes the author bearing witness to one of the lab's many eggs hatching, stating that the infant is "overly concerned" with the Pirate's well-being. Interesting to note is the post-credits cutscene within the same game, showing who is likely Sylux triggering a Metroid egg to hatch in front of him; whether a bond is formed or not is left unknown, but may potentially be answered in Metroid Prime 4.
  • As mentioned previously, the Infant Metroids in Metroid Fusion do not show hostility towards Samus and seemingly do not mind her presence. Due to the fact that Samus' DNA has recently bonded with a Metroid's, it is possible that the Infants detected her genetic makeup and thus view Samus as one of their own. This can be further attributed by the possibility that Metroids at an infant stage perceive their surrounding environment differently from older members of their species; indeed, the Omega Metroid encountered at the end of the game attacked Samus regardless of her genes.
  • Issue 37 of Nintendo Power refers to this stage of the life cycle as a Bantee Metroid, in an early walkthrough of Metroid II: Return of Samus. The description says: "Once you've taken care of the Queen, a new Bantee Metroid will hatch. This one will help you complete your mission."
  • When brought to another planet and/or when exposed to different stimuli (such as Phazon), Infant Metroids either become highly aggressive and resistant or entirely harmless and weak, as was the case with Infant Tallon Metroids and Miniroids, respectively. Also, the mentioned factors render the mutated infants incapable of latching onto any organism and subsequently cannot drain life energy. In the case of the infant Tallon IV strain, it will instead ram itself constantly against prey in an attempt to subdue it.
  • As Samus enters Area 8 in Metroid II: Return of Samus, her Metroid Detector on the bottom right of the screen spontaneously climbs from one to nine Metroids left to hunt. After killing the eight larval Metroids and the Queen, which drops the counter to zero, Samus witnesses the infant Metroid hatch before her eyes, yet the number of Metroids remains unchanged. It would seem the Metroid Detector does not take into account Metroid Hatchlings (for unknown reasons) until these grow to the mature Larval Metroids more commonly seen in other games.
  • The infant stage of a Metroid's life cycle can seemingly be skipped over, as seen during the battle against the Queen Metroid in Metroid: Other M. At the start of the battle, several mature Larval Metroids are instantly spawned from the back of the Queen. They "hatch" from her, making openings on her spinal plating as fluid bursts out. She can still nonetheless lay eggs (seen before the battle) that house infants. This suggests that the Queen creates Metroids in two different manners (one involves giving birth to live Metroids (similar to mammals), the other through the "normal" egg-laying method).
    • Alternatively, after the infants hatch from their eggs the Queen incubates them in the sacs on her back, similar to a joey in a mother kangaroo's pouch, or baby Surinam toads. The mature larval metroids that "hatch" from her back would then have been the same one's that hatched from the eggs seen in the room where the Queen was found.

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