The Zeta Metroid is the fifth stage of a typical Metroid's life cycle. They appear as enemies in Metroid II: Return of Samus, and have a minor appearance in the Restricted Lab of Metroid Fusion. It morphs from the form of a Gamma Metroid, and does so by shedding the previous form like a butterfly sprouting from its chrysalis. The Zeta Metroid has a very different structure from the previous three forms; it gains a bipedal structure with a tail, and its limbs become clawed. The head is separated from the rest of the body by a short neck. In the place of a Gamma Metroid's beak, the Zeta Metroid grows a leech-like mouth. The Zeta Metroid is much smaller than a Gamma Metroid, and gains quite a bit of maneuverability. It also gains the ability to spit large globs of a damaging fluid of some kin