Mega Phoenix

The Mega Phoenix is an item that appears in several games in the series. Whereas a Phoenix Down revives a single fallen ally, the Mega Phoenix item revives all fallen allies.

Final Fantasy VIII
Mega Phoenixes can also be refined to make Phoenix Pinions.

Final Fantasy X
Mega Phoenix is also obtainable through Rikku's Mix Overdrive.

Final Fantasy X-2
Again a valuable rare item, the Mega Phoenix will become available for free from the Alchemist dressphere via the Stash skillset. Mega Phoenix can also be used through the Mix ability.

However, unlike in Final Fantasy X, a Mega Phoenix will not restore all revived characters to full health. Instead, it puts them in critical health (admittedly useful with Cat Nip).

With perfect timing, the user can revive herself with a Mega Phoenix.