Jelzap

The Jelzap is a shark-like aquatic life-form native to Tallon IV which Samus Aran encounters in Metroid Prime. The creature's body consists of two halves made of dense bone and musculature which are impenetrable by Samus' weapons. The top half of the creature's body contains its brain while the bottom half houses the digestive organs; the two halves are connected to each other by a link of electrical impulses which becomes visible as the Jelzap prepares to feed.

Samus cannot harm the Jelzap when its "mouth" is closed, though a charged Power Beam shot or a missile will encourage the creature to open its mouth. When its mouth is open, the Jelzap emits an electromagnetic field that disrupts Samus' visor and actually draws her toward it. It is this ability that allows the Jelzap to lure its prey in, making it Tallon IV's apex predator. The Jelzap is vulnerable only when its mouth is open as the electrical membrane that is its core is visible at this time. Shooting the membrane will kill the Jelzap, leaving the two halves of its body drifting through the water.