Hunter Metroid

Hunter Metroids are adolescent Tallon Metroids, first appearing in Metroid Prime in the Phendrana Drifts area of Tallon IV, and later appearing in the depths of the Phazon Mines and the Impact Crater, where Metroid Prime can freely spawn them in pools of pure Phazon. They have become more efficient at energy draining than younger Tallon Metroids, having developed an energy-siphoning tentacle that enables them to attack from a distance, increasing their threat level. This new tentacle also prevents Samus's Bombs from affecting them. The disadvantage to this tentacle is that Samus can still attack the Hunter Metroid while it's draining her energy. As with most forms of Metroid, the Ice Beam is very effective against Hunter Metroids. These creatures may be related to Metroid Hatchers.

Hunter Metroids are possibly the result of Metroids going through their life-cycle on the planet Tallon IV; rather than advancing to an Alpha Metroid, they evolve into a Hunter Metroid. Another possibility is that exposure to the planet's Phazon contributed to this change in the creatures' life-cycle.

Official website
"As Metroids develop, they become more efficient predators. Hunter Metroids use their energy-draining tentacles to attack their prey from a greater distance than normal Metroids. Quick to anger, a Hunter Metroid will charge troublesome prey and attempt to ram them into submission. Hunter Metroids are averse to cold temperatures. An adolescent energy-based life form with a translucent upper body. Claw-like spikes and an energy-draining tentacle protrude from the lower half of the creature, which it uses to latch onto its prey."

Real-world design

 * Early Metroid concept art also depicts them as tentacled, as well as the Nintendo Comics System.
 * The tentacle may be, in regard to design, derived from the lightning attack of the Gamma Metroid.
 * In Metroid Prime 3: Corruption, there is a new strain of Metroid called Metroid Hatchers. They share a great deal of similarities in appearance, movement and attacks (particularly its energy-siphoning tentacles).

Trivia

 * A Hunter Metroid can be seen on a computer in the Pipeline multiplayer stage of Metroid Prime 2: Echoes and Metroid Prime Trilogy.