A gland in Landing Site Delta, in the Pirate Homeworld Seed.
A gland is an organ inside a Leviathan Seed. They are present in all three Leviathan Landing Sites in Metroid Prime 3: Corruption, in groups of four on the floor. Samus can stand on these glands, which have what appear to be blue, porous pockets of Phazon energy. Scanning them reveals that these glands are capable of generating massive quantities of Phazon. In each Landing Site, Samus finds either Scorchbugs, Phazon Leeches, and Scritters crawling over the glands and the floor. Destroying all of the creatures will reward Samus with a Friend Voucher.
These glands are not seen in the Impact Crater in Metroid Prime, which is presumed to be what remained of Tallon IV's Leviathan after years of decay, nor are they seen anywhere on Aether or Dark Aether in Metroid Prime 2: Echoes, although the presence of a Leviathan there is not apparent (and it is not clear if Samus ever encounters it at all).
Official data[]
Scan (Bryyo Seed/Elysia Seed/Pirate Seed)[]
"One of many glands that is capable of generating massive quantities of Phazon."