Greater Sphere

Greater Sphere is secret enemy in Final Fantasy X which can be bred in the Monster Arena. It look and attacks very similar to the Spherimorph boss from Macalania Woods; the magical alignment rotates following each magic hit. It is, of course, much stonger and will counter all physical attacks with Ultima, and on it's turn will unleash Hydraulic Press which squashes the entire party.

Greater Sphere is unlocked after two Species Conquest monsters are bred.