Dark Trooper

Dark Troopers are Galactic Federation troopers that have been possessed by the Ing Horde. When Samus Aran, who is looking for the missing troopers on Aether, finds them, she discovers that all the troops are deceased. The Ing quickly possess many of the corpses, but are strangely unable to fully complete the possession. Due to this, they have slow reaction times. Despite the fact that their weapon systems are fully functional, the incomplete possession gives them poor aim. They are also equipped with bayonettes, but do not use them frequently. A single, charged Power Beam shot from Samus' Arm Cannon is sufficient to kill them.

When Samus returns to the Splinter Hive after acquiring the Dark Suit, she encounters a Dark Missile Trooper. It is also incompletely possessed, but has greater stamina than his fellow Marines. His Missiles lack the homing ability like Samus's own.

Dark Trooper
"Morphology: Dark Trooper. Deceased GF soldier. Bioscans indicate terminated lifesigns in this trooper, and the presence of an unknown biomass."

Dark Missile Trooper
Metroid Prime 2: Echoes: "Bioscans indicate terminated lifesings in this missile trooper, and the presence of an unknown biomass with parasitic tendencies. Though the missile trooper's armor has been comprimised, the bulk of it remains intact. Missile weapon systems remain online as well. Full parasitic fusion has yet to be obtained, resulting in low agility and response time."

Trivia

 * The Dark Trooper's battle theme has been slightly modified for Metroid Prime Trilogy. Both versions can be found here.
 * The visors of certain Troopers' visors that are unbroken will shatter on the right side and fade completely black to match the uniform model of Dark Troopers.
 * Any Trooper corpse that possesses a Log Book entry will not be possessed. This is so players don't encounter problems finding one-time entries the first time around, especially if they aren't looking for them.
 * The Dark Trooper's slow and shambling gait, as well as the fact that they are dead bodies that rise and attack to begin with, seems to be based on the common media idea of a typical zombie.