Physiology and Behavior
Halzyns appear to have a thin, insect-like bodies in a color ranging from purple to pink. To protect this somewhat fragile body, they have a shell composed of two halves which is impervious to most non-concussive weaponry. Halzyns also fly via unknown means, possibly through vigorously flapping the shell.
In all of their appearances, Halzyns seem to be very aggressive and will try to ram Samus Aran when she comes close.
Halzyns are found in many areas of SR388, including Phase 4, Phase 6, Phase 7, and Phase 8. A Halzyn flies slowly from side to side in a wave-like motion. When it detects Samus, it can slightly increase the speed of its movement pattern in an attempt to hit her. Halzyns can only be harmed if they are shot directly from above or below with Beams and Missiles, thus hitting the main body that their shells do not protect.
In the official remake Metroid: Samus Returns, Halzyns are much less common, now only found in Area 3 and Area 4. They have been redesigned, now more closely resembling their Fusion appearance. Their primary behavior is to fly back and forth in an attempt to find Samus, and to thrust themselves at her either from above or below in a vertical attack. Samus can parry these attacks with her Melee Counter, but can alternatively defeat them with three Missiles or stronger Beam weaponry.
The X Parasites infected and mimicked captured Halzyn specimens in Metroid Fusion. They were only found in two sectors of the BSL Station: the Main Deck and Sector 1. The X mutated the species: infected Halzyns are larger and also boast differently shaped, spiked-shells that cover more of their bodies' surface, as well as having different colors. The infected/copies also have enhanced mobility, allowing them to quickly dive downward when a target moves under them in an attempt to tackle it with their shells. After they crash down, however, the weight of their shells makes it difficult to fly back upward; this forces them to perform flapping motions that greatly expose their vulnerable main bodies. It would seem that the enhanced mobility was gained at the sacrifice of the armors' durability, as they are now weak to missiles.
Metroid II: Return of Samus manual
- Enemies (p. 30)
- "If [sic] flies unsteadyly [sic] in the air. The hard shell on both sides of its body keeps it safe from beams fired its way."
Virtual Console manual
- Enemies (2) (p. 15)
- "This creature flies unsteadily in the air. The shells on its sides keep it safe from beams fired its way."
- Inhabitants & Eco System of SR388 (p. 17)
- "Halzyns, like Motos, are aggressive. They fly back and forth within a limited area, surrounded by two halves of a protective shell. When a threat approaches, a Halzyn closes into its shell and smashes up or down, depending on the location of the threat. Damaging them can be tough, since you need to be right under them to shoot their unprotected bodies. You can outrun and outmaneuver them fairly easily, so feel free to avoid them altogether."
- Walkthrough (p. 88)
- "Halzyns do one thing and one thing only: smash. They move back and forth horizontally and attempt to smash you, be you above or below them. Their predictable behavior makes it easy to determine when they’re going to strike, but that doesn’t mean they’re easy to dodge. They come down at a speed that can catch even veteran bounty hunters off guard. Evasion is an effective tactic, but your safest bet is to take them on directly. When a Halzyn slams down to the ground, it opens itself to a Melee Counter. It comes fast, so keep that finger on the Melee button to nail it and avoid getting smashed into a fine paste."