Gibo

Also called Gibo or Geebo. These enemies are strange living star-shaped bodies of gas consisting 2 parts; an outer body and the inner x-shaped nucleus that occasionally separate each other when they move. Link cannot harm the nucleus nor the cloud when they are together, but they are venerable when they separate - by hitting the nucleus alone, it will then cause both the cloud and the nucleus to be killed.

A Link to the Past
They appear in Thieves' Town in. Their movement is unusual as well; the nucleus separates from the inside of the cloud and moves to a new location independently, while the gas then follows. Both sections of the creature are able to cause damage, but the gas cloud is entirely invincible, and provides protection to the vulnerable nucleus. The Gibo is therefore only vulnerable when it attempts to move. Their awkward movement patterns are made worse by their appearance alongside traps such as moving floors, Winders and Bubbles.

A Link Between Worlds
Gibo appear again in in the Turtle Rock dungeon. Pretty much the same, but instead of the nucleus separating from the body, the body leaves their nucleus first then the nucleus follows, the opposite order of what they do in a Link To the Past. Their appearance reassemble a gel-like substance rather than gas due to the graphics engine unlike A Link To the Past.

Trivia

 * Due to the transparency effect of the Gibo cloud, certain other elements of the game will also become transparent in rooms containing them, such as items dropped by monsters like Fairies and magical effects from the Magic Medallions, among other things.
 * Gibo are sometimes mistaken for Bubbles due to their similar colors and shape.
 * Gibo share some similarities to Morpha from Ocarina of Time, although the Hookshot has no effect on them.