Zeela

Zeela are arthropods sporting long eyestalks. They appear in Metroid, Metroid: Zero Mission, Super Metroid, and Metroid Fusion. They are agile creatures, and can climb walls and hang onto ceilings with little problem. They are native to the Kraid sector of Zebes. Like the near-identical Geemers of Crateria and Norfair, Zeelas seem to be nothing more than indigenous lifeforms, and not a biological weapon used by the Space Pirates.

They come in three known subspecies: Green, Yellow, and Red. They are all identical in behavior to Geemers.

Extinct or Extant?
Zeela seem to have gone extinct when Zebes exploded.

There is very little evidence to support the theory that the Zeela are an extant species. The only Zeela spotted since the destruction of their homeplanet was onboard the Biologic Space Laboratories research station during the events of Metroid Fusion. However, many Zebesian species were also found aboard the vessel. Considering that specimens from the nearby SR388 were also onboard, and the knowledge that these were collected by the scientists, this could be presumed about the Zebesian species, too, as opposed to them being brought onboard by Space Pirates.

Though they were spotted onboard the BSL, these had already been infected by the X Parasite and mimicked, thus creating the Zeela X. The X Parasites seem to have given them a more grotesque look, along with the ability to fire tiny sparks of energy from their sides. If some Zeelas escaped the X infestation, they still met their fates soon after when the BSL was obliterated in its own self-destruct sequence; this means any and all specimens aboard this vessel would be extinct as well.

Metroid Manual
"These boneless animals creep along horizontal and vertical surfaces. They normally live underground. The blue ones are the strongest."

Artificial Intelligence
The AI routine is as follows: The Zeela begins by moving in either the left or right direction. When the Zeela encounters a vertical wall, it rotates by 90° and walks up the wall it hit. Conversely, if the Zeela walks off of a ledge, it rotates -90° and walks down the wall. This allows Zeelas to move in simple circles around a complex room or object.