Eyon

From Wikitroid, the Metroid wiki

Eyons are immobile, energy producing organisms that can be found on walls and ceilings throughout Tallon IV, mainly in the Chozo Ruins.

Eyons produce a focused energy beam that will do minor damage if Samus comes into contact with it. Why it produces this beam other that to hinder movement is a mystery. If any form of weaponry is fired near or on the Eyon will cause a membrane to close shut and disrupt the energy beam. A charged shot can destoy it. How an Eyon gathers food, reproduces, or how it gets to be where it is in the first place is a complete mystery as well. It is however possible that the Eyons aren't biological organisms at all, but cybernetic security systems designed by the Chozo. However, the Chozo went to Tallon IV to escape tecnology so this isn't likely.

Eyons in their appearance of course look like gigantic eyeballs, only instead of being white, they are largely tan colored and have no coloring in its cornea. Its retina also seems much smaller that a usual eye. They seem to have some sort of rooting that attaches it to surfaces.