Phazon Targets (as named in the internal data) are mounted panel devices intended for use as target practice in Hypermode. After awakening from her coma in Metroid Prime 3: Corruption, Samus finds that her body is now generating Phazon, and to take advantage of this, the Galactic Federation has augmented her Power Suit with a Phazon Enhancement Device.
These targets appear in MedLab Delta, forming a sphere in midair. Samus is asked to test her PED Suit's Hyper Beam on them, which uses up an Energy Tank, about the amount of energy needed to destroy all the targets. After being released, Samus walks into the Gunnery Station where five of these are mounted on the walls. They produce Phazon Units and Missile Ammo.
"Mounted panel is invulnerable to standard weapons, but can be damaged by Phazon-based attacks."