Halzyn's Japanese name is "Harasan" (ãƒãƒ©ã‚µãƒ³). "Hara" is Japanese onomatopoeia and used two ways: depicting someone who is in suspense, nervous, or on edge, and describing the motion of fluttering about, so its name is literally, "Mr. Flutter", or "Mr. Flappy".
When the Halzyn was infected by the X parasite in Metroid Fusion, it would close its shell and try to crush Samus if she ran beneath. Due to the Halzyn’s relatively benign antics in Metroid II, it is thought this aggression is attributed to the X parasite mutation.