Leviathan/Kraken
The Leviathan are generally the largest creatures of Magic: the Gathering, often being so big that their lengths are measured in miles, which is reflected in their high power and toughness, the sole exception being the Segovian Leviathan, which is jokingly explained as having come from a very small plane (Segovia never having been referred to before or since except on this card). Leviathans are generally solitary and normally confined to marine environments, though sky leviathans are known to exist on some planes. The Kraken is another monstrous sea species, possibly a subspecies of Leviathan. In the game, despite their considerable sizes, leviathans have never had a presence on the tournament scene as most of them feature a multitude of drawbacks. The B.F.M. (Big Furry Monster), a joke card from the Unglued expansion, wears a Kraken as an earring to demonstrate its size.
(Polar Kraken, Jokulmorder, Sky Swallower, Segovian Leviathan)
Read more about this topic: List Of Species In Magic: The Gathering