Trocra

=Trocra= Trocra are crystalized colonies of cyanobacteria that float in the air. They are found at regular intervals around the arena that holds the first battle with Gorea. If Samus touches them, they will explode, doing damage to her. Trocra do not serve a purpose in the fight until Gorea's Seal Sphere grabs them with energy tendrils and hurls them at Samus, but they can be easily sidestepped.

Alimbic Origins
It is unclear why the Trocra appear in the Seal Sphere room; the Alimbic could have placed them there as a defence against anyone who might want to release Gorea. However, all seven Bounty Hunters were able to get to the Seal Sphere without any hinderance. Because the Trocra are bioweaponry, it is possible that the Alimbic created them at Vesper Defense Outpost.