The Miniroid is the infant stage of a Phazon Metroid. These small, flying mutants are found in the derelict G.F.S. Valhalla and on planet Phaaze in Metroid Prime 3: Corruption.

Miniroids are often found near Phazon Metroids, though contrary to their mature forms, they are entirely non-aggressive and rely on the latter for protection. The bioforms are also extremely frail, thus they always travel in swarms to further increase their chances of survival. Miniroids presumably hatch from Metroid Eggs that have been saturated with Phazon.

Miniroids bear a strong similarity to the more resilient and aggressive Infant Tallon Metroids seen only in Metroid Prime 2: Echoes. Ironically, the latter develops into a form inferior to the Miniroid's next stage.


Miniroids lack many of the unique, physical features seen on mature Phazon Metroids, making the former visually distinct. Their membranes' surface is smooth, possesses a light blue color and is very opaque, making it difficult to view the simple nucleus/nuclei within. Underneath these are four small, brightly pink fangs. Miniroids inhabit the destroyed G.F.S. Valhalla where they likely began to spawn from older Metroid mutants left on the ship after the Space Pirates attacked it. They are also found on Phaaze, but in far greater numbers due to the massive amount of energy present on the planet.

Among the three breeds of infant Metroids seen in the entire series, which includes the unaltered Infant Metroids of SR388 and Infant Tallon Metroids, the Miniroid is by far the weakest and most fragile. Having yet to develop any of their mature form's abilities nor possessing fangs strong enough to disable foes and siphon life energy, they are entirely harmless and never display any hostility toward Samus. In fact, Miniroids are indifferent and unresponsive to any nearby threat, unlike the inquisitive infants from SR388 or the aggressive infant Tallon strain. Miniroids can only harm Samus if she makes physical contact with them, simultaneously causing the former to explode. They will also die from a single shot of any weapon in Samus' Power Suit. Despite their very poor combat capacity and inability to grow rapidly like Infant Tallon Metroids, they eventually mature into the far superior Phazon Metroids and beyond.

Their in-game scan states Miniroids fly in search for sustenance, however due to their lack of attacks, it is possible they simply absorb free forms of energy in their environment, such as the electricity that sparks out of short-circuiting machinery in the G.F.S Valhalla and the ambient Phazon radiation on Phaaze.

Scan data in a Space Pirate laboratory reveals that exposing Metroid Eggs to Phazon mutates the natural infants within. Although only Phazon Metroids are found near the hatched eggs present in the aforementioned lab, the creatures were presumably Miniroids at the time of birth. Another type of egg is mostly seen on Phaaze; described as being highly irradiated with Phazon, they are blue, spherical and very inconsistent in size which insinuates multiple Miniroids may grow in a single one of these.


Logbook entryEdit



Metroid Prime 3: Corruption

Temporary scan

Morphology: Miniroid
Combat rating negligible. Infant has not developed powers.

Logbook entry

Miniroids, tiny and weak, will travel in a flock for protection. They float and fly about in search of sustenance. Those that survive will grow quickly, becoming the feared parasites known throughout the cosmos as Phazon Metroids.


  • In several areas where the previously mentioned blue eggs are located, unknown pulsating cocoons can be found nearby; these are possibly the next step in a Miniroid's life cycle, from which Phazon Metroids or more heavily mutated breeds will emerge.
    • The Japanese version of Metroid Prime 3 states that the Phazon Hopper is an older Hopping Metroid that has reached a reproductive stage. If this is taken as canon, then it is likely that the blue eggs containing Miniroids are laid by Phazon Hoppers.
  • Metroid Hatchers are capable of spawning mature Phazon Metroids. This suggests that Miniroids are first created within the Hatcher's hardened shell and are released when the former grow to their adult stage, unless the Hatcher is capable of making its Phazon Metroids skip the infant stage altogether.