Amorbis

Amorbis is a main arena boss and an antagonist in Metroid Prime 2: Echoes.

Biography
Amorbis is a possessed Sanddigger worm, which the Ing had possessed and used against Samus. Amorbis is first seen lying inert in the Dark Agon Temple on Dark Aether. When Samus uses the Keys to unlock the Temple gate, Amorbis is possessed, and jumps up and begins the fight.

Boss Battle
During the fight Amorbis will use its armour to attack and defend itself. It spits out lasers of dark magic which can seriously damage Samus if they hit her. Also the Amorbis also is actually three possessed worms, thus making it doubly difficult.

Samus will have to blast missiles at the Amorbis' head armour to damage it, and then it will fall to the ground inert and Samus can roll in its suction filled jaws when in the Morph Ball form. Once inside, Samus must lay a bomb, which will chew off a large amount of Amorbis' health.

When Amorbis is nearly defeated, it will go through a large amount of jumping around the earth, and it becomes faster and much difficult to fathom where it will appear next. When it is next grouped round the Dark Sphere, Samus must bomb its head armour until vulnerable. When all three heads have been bombed by the Morph Ball, two worms will mysteriously vanish into the sand and the main one will explode.

What's left is the Dark Suit, which will protect Samus further from Dark Aether's atmosphere.

Behind the scenes
Because of the rapidity of the fight, the amount of damage taken when hit by Amorbis (which can happen a lot) and the distance it takes to get pick ups, and the toxic atmosphere of Dark Aether as well as the few Energy Tanks available before the fight, this, along with the Boost Guardian, is considered a really difficult boss, but easy enough if one is fast enough.

Trivia

 * Amorbis is similar to the Graboids from Tremors.
 * Amorbis could be a pun on "amorphous" because the Ing before possession are an amorphous dark mass.