Polyp is the name provided to the small, spherical projectiles ejected from a specific type of structure on the ground. They are found exclusively within Norfair on Zebes in Metroid and its remake, Metroid: Zero Mission.

The structure that launches Polyps is referred to as an Air Hole, sharing the same name as the very different but far more common "nest" openings that release various different bioforms.

Description

Metroid

In the NES/FDS game, the sprite of the Polyps' Air Holes resemble Red Hatches facing upwards, and their artwork in both the manual and Japanese guide clearly depicts them as being mechanical, with a small hatch at their center that cannot be seen during gameplay, due to the side angle view. The Polyps themselves are launched from the mentioned hatch and are energy-based constructs in artwork, though their in-game sprite is more difficult to discern.

Only the Polyps are harmful on contact, but they, along with their Air Holes, are impervious to Samus Aran's weapons. This leaves her with no choice but to jump over them to avoid getting hit, which can be difficult depending on the version of the game: in the FDS version, numerous Polyps are tossed erratically and randomly at both left and right sides of the structure at varying arcs, making the sequence akin to an erupting volcano; meanwhile, the NES version restricts them to being tossed only on one side at the same arc in a single file. These differences are due to the lower specs of the NES console creating repetitive and predictable enemy behaviors. In both versions, Polyps are launched regardless if Samus is close by, and there is a short break after each volley.

Metroid: Zero Mission

The Polyps and their Air Holes have very different designs in the GBA remake: the former resemble small dark purple Item Spheres, and the latter have a segmented beige tube protruding from a red structure's oval opening. The nature of these Air Holes is uncertain, due to how they slowly contract and relax in their idle animation, a behavior that makes them seem like living entities.

When Samus gets near, the Air Hole's tube retracts and then immediately extends outward to toss its arcing projectile. Only a single, destructible Polyp is produced every cycle, and it travels at a slower speed than in the original game. The Air Hole can also destroyed, but only with a Missile or the Screw Attack, and can be frozen with the Ice Beam as well; if Samus steps on one, she will flinch as if she is harmed, but no damage is actually inflicted.

Miscellaneous info

In all games featuring Polyps, it can be assumed at first glance that their Air Holes are a type of ventilation system connected to an unseen source of Polyps, or the Air Holes create their projectiles from the material directly below them, such as in Zero Mission, where one can be seen attached to the ground on top of lava. There are instances, however, where they are located on small floating platforms, revealing the Polyps are somehow infinitely produced within the very structure that launches them, which is a minuscule amount of space. While the Polyps' original depiction as energy may have made their infinite numbers more plausible, their appearance in the remake as physical objects makes their production an enigma.

This is shared with the more widespread pipe-like Air Holes: a few of these have organisms emerge unceasingly from within seemingly impossible space.

Official data

Metroid manual

Polyp

"These are poisonous lumps of lava that are blown out of the air holes. They are weak enemies and have no life force."

Victory Techniques for Metroid

"Poisonous lava flies out of this vent. Be careful because it will appear suddenly."

Etymology

The word "Polyp" is also the name of a real-life creature. When amassed in great quantities, real polyps create a coral structure. "Polyp" may also refer to a type of tumor or a hypertrophy of the mucous membrane.

Trivia

• Entities known as Puromi appear in Super Metroid, consisting of numerous spheres that slowly travel at an arc in single file, making them nearly identical to the NES version of the Polyps. It is unknown if the two enemies are related.

Gallery

Indestructible Creatures
Non-hostile	Aurora Unit 217 • Baby • Dachora • Databot • Etecoon • Fleet Admiral Castor Dane • Fleet Mechanic • Pow • Septogg • Tatori • Tatori, Jr. • U-Mos Training Drone • Watchdrone • Work Robot
Hostiles	Aazelion • Airthorn • Autom • Big Metroid • Cannon • GMX-04 Halberd-class turret (if provoked) • Polyp • Proboscum Puromi • Ring Beam Unit • Ripper II • Samus Eater (Bud) • Seed platform • Unfreezable Metroid • ZipNMEBomber
Misc.	Bloatsac • Blueroot Tree (Dark) • Butterfly • Chomper Fish • Durable plantform • Fish • Fungus • Glow Stem • Great Tree Massive tentacle • Moth • Parasitic fungus • Protozoan • RedGrass • Sandgrass • Sbug • Scarp • Scatterbug • Tallon fern • Mantha