Archeoaevis

Archeoaevis is a winged serpent creature that first appears in Final Fantasy V as a boss and in Final Fantasy XII and subsequent titles as an enemy.

Final Fantasy V
In Final Fantasy V, Archeoaevis is fought at Ronka Ruins in Bartz's World where it guards the Earth Crystal.

The battle against Archeoaevis has five different phases, and its stats, namely its elemental weakness, are different for each one as well as its attacks. During the first phase, Archeoaevis uses Breath Wing and Sap, and it has a weakness to Wind, making this the only phase where Archeoaevis has a weakness. In the second phase, Archeoaevis uses Frost and Wing Attack. In the third phase, Archeoaevis uses Blaze and Tail. In the fourth phase, Archeoaevis uses Lightning and Claw.

After the fourth phase, Archeoaevis is defeated, only to be immediately resurrected as an undead creature for a fifth and final phase. During this phase, Archeoaevis retains one move from each of the four earlier phases — Breath Wing, Frost, Blaze, and Lightning — and uses three additional moves, Maelstrom, Entangle, and Tusk. As an undead creature, Archeoaevis can instantly be defeated from the move Death.

In the bestiary, which first appears in the Final Fantasy V Advance release, Archeoaevis's page lists its stats for each of the five phases. Each of them list Archeoaevis's HP with a question mark, although the Nintendo Player's Guide says that Archeoaevis has only 1,600 HP, since it erroneously shows Archeoaevis's stats for only the first phase. During Archeoaevis's undead phase, he has 2,500 HP. In total, Archeoaevis has 8,900 HP.