Greater Sphere is an enemy in Final Fantasy X, bred in the Original Creation at Monster Arena. It looks and attacks similar to the Spherimorph boss from Macalania Woods. Greater Sphere is unlocked after two Species Conquest monsters are bred.
The Greater Sphere is vulnerable to an element, but shifts it randomly once hit by its weakness. Unlike the Spherimorph, the Greater Sphere absorbs any other element. After the Greater Sphere attacks with an elemental attack, it will be weak to that attack's opposite element.
It will counter all normal attacks with Ultima. On its turn it will alternate between a normal attack and unleashing Hydraulic Press, which deals fractional damage to the entire party, equal to 15/16 of each character's maximum HP. For every Overdrive the Greater Sphere survives it will counter with Hydraulic Press.
It drops weapons with One MP Cost and armor with Auto-Phoenix. Its equipment drops provide a 6% critical hit chance bonus instead of the usual 3% (this is relevant to weapons and armor, but only to attacks that deal physical damage).
The Greater Sphere is unusually time consuming to defeat and very powerful. Auto-abilities such as Break HP Limit, Auto-Haste, Auto-Protect, and Auto-Shell prove helpful, and a high Magic Defense attribute is vital. Before attacking Greater Sphere, the player should be prepared to weather Ultima as a counterattack.
Tidus's and Wakka's Overdrives, Blitz Ace and Attack Reels respectively, can hasten the battle significantly. Another helpful strategy is to summon Anima and cast Protect and Haste. If Anima loses health, she should cast Curaga. She should use Oblivion when it becomes available. This strategy is only viable in the International/PAL/HD versions.