Megalixir

The Megalixir is a recurring item in the Final Fantasy series. It usually completely restores the HP and MP of all allies. Because of this, it is often very rare.

Final Fantasy
The Megalixir only appears in the Dawn of Souls and 20th Anniversary versions, and can only be found in the new secret dungeons and the Chaos Shrine.

Final Fantasy IV
The Megalixir appears in the game's Advance release, found in the Cave of Trials and the Lunar Ruins. In the DS release, it can be stolen from Proto-Babil and serves as a map completion reward.

Final Fantasy IV: The After Years
Megalixirs restore all HP and MP to the party and can be found as a possible reward in the second Lunarian Challenge Dungeon, or otherwise as a very rare drop from Sahagin Princes and Great Malboros.

Final Fantasy VI
Betting it in the Coliseum makes the player fight Siegfried.

Final Fantasy VII
There are an unusually high amount of Megalixirs to be found in this game, with at least a dozen available for player use. In the PlayStation version of Final Fantasy VII, the player can find a chest containing a Last Elixir within Gaea's Cliff. This is a mistake, as a normal Megalixir is added to the player's inventory instead.

Final Fantasy X
In addition to being a regular item, the Megalixir can also be created through Rikku's Mix Overdrive.

Final Fantasy X-2
Megalixirs cannot be bought from shops but can be sold for 5,000 gil.

Megalixir+ is a result from Lady Luck's Item Reels by rolling to three Red 7s. It recovers up to 9999 HP and up to 999 MP to ally party; any KOs are revived. A regular Megalixir is achieved by lining three blue flasks.

Final Fantasy XI
The Megalixir will fully restore the user's HP and MP (but not party members). It is only available as a temporary item during certain events such as Besieged.

Final Fantasy XII
The Megalixir is a very rare item that requires rare loot to make at the bazaar. The only other places they can be obtained are as a reward from the Gilgamesh and Belito Hunts and as a rare treasure chest item. There is a reappearing chest on the Cerobi Steppe that has a decent chance of giving the party a Megalixir, even without the use of the Diamond Armlet. In the deep end of the Henne Mines, the player may also find Megalixirs in the areas before Zodiark.

To make in the bazaar, the player would need to sell 2x High Arcana, 3x Rat Tail and 3x Onion. It costs 108,000 gil and the pack can be created repeatedly.

Bravely Default
It fully restores the party's HP and MP. Outside of Bravely Second, it restores (or damages, if undead) 9999 HP and 999 MP. However, in Bravely Second, it will restore 999999 HP.

Dissidia Final Fantasy
Megalixir is a trade accessory that grants +4 Luck and can be traded with another high-quality trade accessories.

Dissidia 012 Final Fantasy
Megalixir is a trade accessory that grants +4 Luck when equipped, and can only be found in the Moogle Shop. It is required for higher-quality accessories.