Midgardsormr

Midgardsormr (ミドガルズオルム), also named Jorgandr, is a serpent enemy in the Final Fantasy franchise. It first appears in the game The Final Fantasy Legend, and its first main series appearance is in Final Fantasy VI. Midgardsormr is based on, a sea serpent from Norse mythology.

Final Fantasy VI
In Final Fantasy VI, Midgarsormr (named Terrato in the Super Nintendo and PlayStation versions) appears as a esper. Its magicite appears in the Yeti's Cave. The magicite is in possession of Umaro, so when the party obtains it, Umaro comes out to attack them. After the battle, the Midgardsormr magicite can be equipped. If Mog is with the party, he convinces Umaro to join them.

During a battle, it costs 40 MP for a party member to summon Midgardsormr. When summoned, it uses the attack, which deals Earth-elemental damage to all opponents. Midgardsormr allows for its user's HP to increase by 30% whenever they level up. Midgardsormr also teaches Quake at a 3x rate and both Graviga and Tornado at a x1 rate.