Metroid Database Bestiary

Fune-X and Namihe-X are long, snake-like creatures that reside in walls. Funes do not have eyes, so they rely on their keen sense of hearing and their ability to sense vibrations in the air to attack their prey. Unlike the ones encountered on Zebes, Fune-X can elongate their bodies very quickly. It is possible that the X gave the Fune this ability when it copied them.

Most Fune-X encountered are positioned to be frozen with Ice Missiles and then used as platforms. You can trick them to extend out first by quickly jumping in front of them.