Amorbis

Amorbis are worm-like creatures in Metroid Prime 2: Echoes. Three of them are fought as the Boss of the Dark Agon Wastes on Dark Aether where they serves as the guardians of the Dark Agon Temple. Once defeated, Samus Aran is rewarded with the Dark Suit and the access to the Dark Agon Temple. Amorbis used to be Luminoth guardians before the split of Aether and Dark Aether, a statue of an Amorbis built by the Luminoth can be found on the Mining Plaza and it was revealed in an interview that the Light Suit design was based on the Amorbis.

Battle
At first, only one Amorbis is actively attacking Samus while the other two are burrowed under the ground. To defeat the Amorbis, Samus must simply shoot it while it is tunneling in and out of the earth. After receiving enough damage, the Amorbis will attach itself to the Dark Sphere in the center of the arena and charge itself with dark energy to eventually become a Darkling and grow a layer of thick dark armor on all of their body and can now cover Light Crystals with sludge.

At this point, only the head layer of the Amorbis can be destroyed thanks to Samus' Light Beam, Power Beam or Missiles. After its crown is destroyed, Amorbis will lay down and start sucking air and sand to reform its crown, Samus must use the Morph Ball to get inside its mouth and lay Bombs inside it. Once this is complete, Amorbis will spit her out and violently convulse, involuntarily damaging the Dark Sphere in the process by lifting it and slamming it down against the ground. Samus will then need to repeat this with a second Amorbis and then the third one, while more than one Amorbis is attached to the Dark Sphere, they will be able to fire lasers from their crowns. Once the three are dealt with, they will all die and the Dark Sphere will crack open, releasing the the Dark Suit that was trapped inside it.

Amorbis
"The enormous Amorbis can move through solid rock and earth with ease, and can sense the location of surface-level prey deep within the ground. They will attempt to ram any target they can find in their domain. They are vulnerable to all forms of weapons fire, but are incredibly strong and resistant to pain."

Dark Amorbis
"The Amorbis can attach themselves to the Dark Sphere, drawing potent energy from within. They can fire dark energy at Light Crystals, nullifying Safe Zones for a short time. They can also channel this energy into powerful beam attacks. Bioscans indicate a weak spot inside the creature’s mouth. Concentrate your fire at this area to damage an Amorbis."