Ghalmanians are first encountered in Sector 1, where they break the glass in the confrontation room as they enter and their mischievous giggle-like cry can be heard. One of them will then use its tail grapple attack on Samus, starting a battle.
A Ghalmanian will normally fight by headbutting, spitting acid, and striking with its claw-shaped tongue. It also have a grab attack performed with its tail - if successful, it will swing Samus in circles before throwing her into the ground. If Samus performs a Counter Attack, she will spin the Ghalmanian around by its tail instead and throw it, causing light damage and stunning it. Samus can Overblast these creatures, but if she fails to fire in time, it will perform a reversal by bucking her off and whipping her away with its tail. Once stunned, it can be finished with a Lethal Strike.
However, after taking some damage it will quickly use camouflage to become invisible. While invisible it can still be hit and will continue to spit globs of acid at Samus, which she can use to pinpoint its location and hit it with a Missile to render it visible again. It may turn invisible multiple times throughout a fight, depending on the duration thereof.
They are encountered many times in the game. The first instance is where she fights them in the "confrontation room", and in another instance, Samus dislodges a broken elevator to crush a Ghalmanian (crushing her as well if she does not jump into an alcove). She also fights two in the Subterranean Control Room. Several Ghalmanians are called to the Bioweapon Research Center shortly before the fight with MB (although Samus does not engage them; they appear in a cutscene), and Ghalmanians also attack Samus on her return to the BOTTLE SHIP in the "path of perils" on the way to the Control Bridge.
"Ghalmanians are chameleon type creatures that can change the color of their body. When they are transparent, they'll launch acid in your direction. Counter with a missile."
- Interesting to note, both their tails and tongues are twice the length of the rest of their bodies, and yet they maintain their balance perfectly.
- The tongue of a Ghalmanian also appears to have a mechanical grappling claw affixed to the end.
- Interestingly, the creatures seem to be carrying armor pieces on their bodies. This, along with the mentioned grappling claw on the tip of their tongues, suggest that scientists on board the BOTTLE SHIP added these artificial structures, possibly to turn Ghalmanians into efficient bioweapons.
- Ghalmanians are one of the few enemies who Samus targets in a location other than the head or neck during an Overblast, instead targeting the base of its tail.
- While no Ghalmanians appear at the Exam Center, odd cases with the name "Ghalmanian" can be found in broken vending machines and on the floor in the Center, alongside what appears to be food.
- This creature shares many similarities with another lizard-like creature, such as skin color, green armor-like parts on their bodies, a long tongue, using its tail as a main weapon in battle and its reptilian appearance.
- In the first encounter with a Ghalmanian in the BOTTLE SHIP's Biosphere, during the cinematic, the creature uses its long tail to snare Samus and toss her if no action is taken by the player. However, if the 1 Button is pressed on the Wii Remote at the right moment, Samus can turn the tide on the battle by grabbing the Ghalmanian’s tail and tossing it, leaving it open for a Lethal Strike. This can easily be achieved by pressing the 1 Button rapidly during the cinematic.
- Artwork of a Ghalmanian is featured on Metroid Mug 2010.
- The Ghalmanian fought in the elevator room can be killed by the elevator and normal attacks, but the time taken to kill it using Samus's normal attacks will not allow her to get out of the elevator's way in time, as Samus cannot see the Ghalmanian from the spot that she stands at to destroy the elevator supports.
- In the same battle, if the Ghalmanian reaches the top, it will hit the wedge and explode, causing the elevator to drop.
- Also in the same battle, if the Ghalmanian reaches to the highest alcove and if Samus is standing there, it will grab her with its tail and throw her at the wedge, causing the elevator to dislodge and crush them both.
- The Ghalmanian's Japanese name includes the kanji 星人, which is shared with Zebesian, Kyratian, and Griptian. Similarly, their English names end with the -ian suffix. Since this name indicates that the Zebesian is an inhabitant of Zebes, this may imply that Ghalmanians are native to a (currently-unseen) planet named Garuman (ガルマン) or Ghalman.