Kihunter

Kihunters (occasionally called Keyhunters or Ki-Hunters in some early media) are a type of enemy that appear in Super Metroid, Metroid Fusion,and Metroid: Other M.

History
Keyhunters are allies of Space Pirates and hail from another galactic system; according to Super Metroid ' s manual, they are pirates from another galaxy. Whether this means they are Space Pirates (as a species) or merely in profession is unknown. Known planets they inhabit are Zebes. They have wings, allowing them to fly, and can spit acid from their mouth, though they mainly charge their opponents while swiping at them with their claws. If they lose their wings, they will only spit acid and travel by hopping.

In Super Metroid, they can be found in large numbers in Crateria, Brinstar, the Wrecked Ship and Lower Norfair. Their colors seem to adapt and blend in with the surrounding areas.

In Metroid Fusion, Keyhunters have been infected and mimicked by X Parasites. These Keyhunter X have a slightly different head structure from the ones seen on Zebes; they now possess a beak-like structure for a mouth and their foreheads are colored purple instead of yellow. They can be found in Sector 2 and parts of the Main Deck of the Biologic Space Laboratories research station. However, prior to their appearances, Samus encounters X infected/mimicked Zoros at first. These caterpillar-like creatures are eventually witnessed entering a pupa stage and later on hatching from their cocoons as Keyhunters (still containing X Parasites): this sequence of events reveals that Zoros are actually infant/larval Keyhunters.

Kihunters also appear in Metroid: Other M in their first 3D appearance. They are often found near Zeros, their larval stage. There is also a bulbous Kihunter known as King Kihunter found inside their hive.

Samus indicates surprise at encountering them, wondering about the return of the "beelike creatures."

Prime series
A similar-looking Space Pirate appears in concept art for what may be the Flying Pirate in Metroid Prime. This "Keyhunter" has shorter wings, longer legs, and a Metroid strapped to its back.

Weavel, a Space Pirate bounty hunter from Metroid Prime: Hunters, wears a Power Suit vaguely resembling a Keyhunter.

Variations
Super Kihunters are featured in Other M. They are generally more durable, with crystalized structures and are colored green (regular Kihunters in Other M are instead blue). These seem to be an advanced stage of the Kihunters' life cycle onboard the Bottle Ship.

Trivia

 * The room directly before facing the Spore Spawn is filled with Keyhunters and small, unknown structures on the ceiling resembling eggs. Since both the flying creatures and the egg-like objects are found in the same room, it is possible that the latter are Keyhunter eggs.
 * While Kihunters are known to be Space Pirates in Super Metroid, Samus curiously makes no mention of this in Other M. In fact, Kihunters appear to have no affiliation with Space Pirates in that game and in Metroid Fusion. However, their feral nature in both games can be easily explained by the lack of a proper education and/or a supreme Pirate leader, just as how Zebesians in the Bottle Ship are steadily losing their intelligence without the presence of the Mother Brain.


 * The areas Kihunters inhabit in Super Metroid are either largely organic or (in the case of the Wrecked Ship) long since abandoned and infested with wildlife.

Super Metroid manual
SPACE PIRATES - KEYHUNTERS

"These creatures are pirates from another galactic system who helped rebuild Zebes. When they lose their wings, they spit powerful acid."

Super Metroid Nintendo Player's Guide
"Kihunters are fairly powerful and painfully persistent. Shoot them with Charge Beam shots."