The Parasite Queen is the first boss, encountered on the Frigate Orpheon. She is encased in a protective shell. Her weak points are the glowing segments on her tentacles. Focus Power Beam shots on these. When she opens her mouth to charge an energy blast, fire a charged shot or a Missile directly into her mouth for massive damage. Strafe constantly to avoid her energy projectiles. This fight is a good introduction to lock-on combat and weak point targeting.
While the Parasite Queen represents a localized mutation, her parasitic nature mirrors the X Parasites encountered in Metroid Fusion that eventually reshape Samus Aran’s biological makeup.