Berserker Knight

Berserker Knights were elite Space Pirates that had been heavily mutated by Phazon radiation. These hulking monstrosities appeared in Metroid Prime 3: Corruption.

Description
Due to Space Pirates conducting experiments on their own kind with Phazon, they were able to create powerful, hulking soldiers known as Berserker Knights. Like their lesser Pirate comrades, they possess crustacean-like characteristics, seen in the way their mandibles are split, along with their pincers. They have an immense upper body with large imposing arms, while possessing a noticeably small, lower body. Their shoulders are equipped with a weapon system that fires homing, Phazon-based projectiles. They have Phazite plating on their weak spot, which lies above the back of their heads. Some Berserker Knights become Berserker Lords after surviving the highest levels of Phazon corruption.

Appearance aside (Berserker Knights appear more brown whereas Berserker Lords are blue) the only difference between Berserker Knights and Berserker Lords is that Knights lack the orbs of energy on their shoulders that must be destroyed. This relatively simple difference makes battles with Knights considerably shorter than Lords, especially since they cannot regenerate these orbs after their phazite plating has been partially damaged. The common way to break the plating is by shooting the purple orbs fired by the creature; doing so will send the orbs flying toward the plating. After its destruction, the weak spot will be open to attack. However with the use of the X-Ray Visor in combination with the Nova Beam, Samus can target an organ to instantly kill the creature.

They are similar to Elite Pirates by playing the same role. They also show little to no concern for their fellow Space Pirates and will even use them as projectiles. This is likely due to Phazon infusion having deteriorated their brain tissue, resulting in an increase to their lust for combat, giving them the name Berserker.

Oddly, despite the Space Pirates in the original Prime being very hunched, the Elite Pirates stand tall and are not so hunched. On the other hand, the Pirates in Corruption are less hunched (only the neck is bent) and the Berserker Knights and Lords are very bent in structure. It is believed that even after the events of Metroid Prime, the Pirates continued Project Helix in some shape or form and gave birth to Berserker Knights and Berserker Lords, subsequently replacing the Omega and Elite Pirates.