This article refers to the natural infant life cycle stage of the Metroid. For the specific infant Metroid encountered in SR388 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 small size gives it a harmless appearance, yet its conduct and threat level are, in actuality, very difficult to assess. Regardless, after an undetermined amount of time, an infant will grow into the most common stage of the species' life cycle: the vicious Larva Metroid.

In their homeworld of SR388, Hatchlings seemingly do not stray far from their parent, unless they are relocated elsewhere by outside intervention. As such, they have rarely been encountered in the Metroid series by Samus Aran.

Morphology and behavior Edit

An infant's body consists of a transparent, green and/or blue membrane that surrounds four minuscule red nuclei. Underneath the red organs is a small mass of tissue with two pairs of tiny fangs protruding on the underside.

The original design for the infants seen in both Metroid II: Return of Samus and its concept art gave it significantly less neuron-like connections between its membrane and nuclei than the Larval stage, and featured only a single pair of fangs.

At first sight, a Metroid Hatchling appears to be harmless; in the presence of an unrelated organism, the Metroid will circle around it and observe with great curiosity. While this behavior leaves it highly vulnerable, it can quickly become unpredictable and may strike without warning in order to devour its prey's life energy. Due to its young age however, an infant has yet to develop the massively strong grip seen in Larva Metroids and can consequently be removed by hand if one possesses sufficient strength, as demonstrated by Proteus Ridley. Their weak strength can be remedied if multiple Infant Metroids converge on the same target simultaneously, as they will severely hinder their prey's capacity to attack and remove them; this strategy was successfully applied against an SA-X.

Contrary to the highly resilient Larva Metroids which require 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 forms of weaponry.

Though rarely demonstrated, Metroids are known to be capable of giving their stored life energy to injured organisms in order to heal them, and this ability can manifest as early as the Infant stage.

Chronological appearances Edit

Metroid Prime: Federation Force Edit

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. Initially acquired from a Space Pirate research site by the Federation Forces on the planet Talvania, the egg promptly hatches after the infiltrator uses a focused beam on it. The fate of both this Infant Metroid and the infiltrator have yet to be revealed.

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.

Metroid II: Return of Samus & Metroid: Samus Returns Edit


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 Infant Metroid during a mission to SR388, the species' homeworld.

Main article: Baby

Despite being tasked with rendering the native Metroids extinct, Samus hesitated when she happened upon the very last Metroid left on the planet emerging from its egg in front of her. Never having come across a natural infant before this moment, Samus was caught completely off-guard by its confused, curious yet playful and childlike behavior. These traits were never seen in any Metroid she killed over the years, including the mutated strains that remotely resembled a hatchling: the Infant Tallon Metroids and Miniroids, which reacted with high aggression and total indifference to her presence, respectively.

The native Infant Metroid did not harm Samus and went as far as imprinting onto her, giving the impression of a creature physically incapable of posing any threat. It ultimately proved the opposite when it unpredictably attacked Proteus Ridley, draining and transferring portions of his life energy to Samus near the end of her battle against him.

Super MetroidEdit

Metroid small

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. Interestingly, the mutant could produce the same cries as an infant after recognizing Samus, though some of these were in a deeper pitch to reflect its bigger size.

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 worthy to note that Adam theorizes that the infant may have been one of the genetically modified specimens that would have grown into an Unfreezable Metroid, however it was impossible to confirm at such an early stage due to Infant Metroids of both natural and cold-resistant groups being identical.

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 in taming the infants. However, the bonds themselves are presumed to have left a significant impact on the android, possibly on an emotional level.

Metroid Fusion Edit

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 kept in suspended animation.

An X Parasite mimicking Samus quickly located the lab as well and wreaked havoc with its weapons. While it seemingly managed to kill several Infants, the destruction caused by the SA-X broke every containment glass and freed all remaining hatchlings. Though they initially flew around the room harmlessly and erratically to avoid the SA-X's projectiles, a small group of Infant Metroids suddenly swarmed and overwhelmed their attacker. As they fed on the writhing mimic, Samus climbed to the top of the lab where more Infant Metroids roamed freely in the air, and while they never showed hostility to her, 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 it suffciently distanced 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 proceed to devour all X Parasites in its path as it molted through its life cycle. Due to the modifications made to the Metroids onboard the BSL by its scientists, (as hinted by the computerized Adam), it metamorphosed at an unnaturally rapid rate 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.


  • 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 unrelated individual in front of a hatching egg. This was attempted between the android known as MB and an unknown number of Infant Metroids. However, due to the fact that all Larva Metroids seen in the same game were never present in the same room as MB, the strength of their bond was 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 eggs hatching, stating that the newborn 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.
  • Despite the presence of hatched Metroid Eggs within the Queen Metroid's room in Other M, there were no infants to be found. Instead, Larva Metroids were seen bursting out of the Queen's dorsal plates. Due to these elements, it can be logically assumed that at some point after hatching, Infant Metroids enter the pits on their mother's back, where they are possibly nurtured until they reach the larva stage.
    • The missing Infant Metroids during Samus' encounter with the Queen and the larvae breaking out of their mother's back, which is visually akin to the hatching of an egg, may give the false impression that the present Larva Metroids skipped the Infant form entirely and were born directly in the third stage of their life-cycle.
  • 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."
  • Unlike an Infant Metroid, the similar Infant Tallon Metroid and Miniroid mutant strains are incapable of latching onto organisms 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, while the Miniroid possibly acquires its nourishment from absorbing free forms of energy emanating from their surroundings.
  • 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 Larva 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 until these grow to their larval stage commonly seen in other games. Therefore, the Metroid Detector's sudden increase in numbers implies that the additional larvae were all Infant Metroids mere seconds ago.
  • 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 Larva Metroids are instantly spawned from the spinal plating of the Queen. They "hatch" from her, creating openings on her back as fluids burst out. She can still nonetheless lay eggs that house infants, as evidenced by the hatched eggs seen prior to the battle. This suggests that the Queen gives birth to Metroids in two different manners: one that involves giving birth to live Metroids in a similar fashion to mammals, and the other through the egg-laying method.
    • Alternatively, after the infants hatch from their eggs, the Queen potentially incubates them in the sacs on her back, similar to a joey in a mother kangaroo's pouch, or baby Surinam toads. Thus, when the infants mature into their larva form, they "hatch" from her back; this would imply that the hatched eggs seen in Room MW belonged to the larvae that fight alongside the Queen.