[header] How to defeat all bosses in metroid prime 3 [title] Shoot the two red shoulder joints that glow very brightly. [step] These are its only weak points for now and must be hit to move on to the next phase, as other parts of its body are immune to all conventional weaponry. [title] Dodge the attacks that it uses to damage you. 
[substeps] Jump if it shoots out a focused laser beam. Sidestep left and right if it uses melee attacks move away if it squirts out phazon at you, and jump twice to hop over its shock wave.