Metroid Database Bestiary

Large flying predator that lives in the pipes and air vents of Brinstar. Communal, Geegas nest in large numbers, clinging to the curve of the pipes for warmth. Their sensitive antennae can detect the subtle atmospheric vibrations of prey moving near their dens, and their eyes are sensitive to the dim light of Brinstar. This fearsome creature will attack in force if disturbed, and even a handful of Geegas can rip large prey to pieces in a matter of seconds. Extreme caution is advised around air vents and other piping, as they often strike quickly and unexpectedly.

Geegas don't pose much of a threat beyond succeeding at being extremely annoying. They fly very quickly, so be on the lookout when you see horizontal pipes throughout Brinstar. Use a few Beam Shots to take them out.

Sprites for the Geega-X were found in the game data of Metroid Fusion. It seems it's just another one of those things that was left on the cutting room floor.