Okay, so the only time she tried to commit genocide against them, she took pity on the last baby Metroid and handed it over to the federation, which led to the slaughter of the entire space colony. Of course, she also made the choice to wipe them out when she chose to crash the BSE space colony into their home planet in Metroid fusion, even though her real intention was to wipe out all the Parasite X.
Damn! That's a BIIIIG Bitch!
believe me, that's just a small one.
not that small, hatched metroids are about the size of your fist (from metroid prime 2) they become dangerous in the second phase of their development, the one in the comic above, but i think they range from about the size of your head to a golf cart, depending on age and the amount of energy they take in. I'm not sure about the later phases in the metroid life cycle, but apparently they become huge bipedal monsters (the omega metroid from the end of metroid fusion) I also heard of a queen metroid, but i never actually saw one, and metroid prime is probably a subspecies or something, since its similar in morphology to a metroid (once you blast away the exoskeleton) and can communicate with them
It seems the ONLY type of genocide that's ever easy are those one defenseless civilians...>_<
There's probably an area where it splits up and turns into Komatoes from Kid Icarus.