Halzyn are flying organisms that keep aloft through vigorous wing flaps, flying unsteadily in the air. These wings double as a defensive measure by being covered in a hard shell that protect it from predators and doubles as protection against weaponry such as beam technology from the sides.
They were collected aboard the Biologic Space Laboratory Research Station by the scientists stationed aboard it, but when the X Parasite overtook the station, the Halzyn were infested just like everything else (besides the Metroids - as they are the main predators of the X - and the Etecoons and Dachoras, which were safely locked away). Halzyn-X boast stronger, spiked shells and they have adapted to drop downward when a target moves underneath it. However, this new tactic does leave them vulnerable, as the added weight of the shell makes it difficult for them to fly back up again. Also, the shell on this version can be destroyed, leaving its body exposed.
Because both its homeworld and the only place it has ever been spotted offworld have both been (presumably) destroyed (the evidence of SR388's destruction was not witnessed first-hand by Samus Aran, it can be assumed that it is now officially considered extinct.