Stormtide Leviathan is a rare Creature — Leviathan card from Magic 2015 (M15), collector number 80. Current market price: $0.49 (foil $4.69), TCGplayer market prices via Scryfall.
Islandwalk (This creature can't be blocked as long as defending player controls an Island.) All lands are Islands in addition to their other types. Creatures without flying or islandwalk can't attack.