Leviathan

Leviathan (, Leviathan) is a summon from the series.

Origin
A giant sea serpent, he first appears as a monster that swallowed the party in Final Fantasy II, and went on to become one of the most prominent summons alongside Bahamut. Given titles such as "The Sea King", or "Lord of All Waters". In the later titles Leviathan's appearances in the series started to become lesser as Bahamut gained more status and popularity. Leviathan's trademark attack is Tsunami which is also called Tidal Wave, which calls on a massive wave of water to damage all enemies.

In Final Fantasy VII, The Leviathan Summon Materia is obtained in Wutai after Yuffie defeats the fifth and last pagoda god, Godo. It casts Tidal Wave and costs 78 MP. Leviathan's spell power is equal to 4.6875x the base magic damage.

As a stage element
Leviathan appears as one of the summons on Midgar. When he appears, he floods the stage and causes it to surf across a body of water.