Leviathan [Fourth Edition (Foreign Black Border)] Rogue Rat Sacrifice another Serpent or Squirrel:

Sacrifice another Serpent or Squirrel: Choose one —

Set: Ixalan Prerelease Promos Type: Creature — Human Pirate Rarity: Rare Cost: {3}{R} {3}{R}: Gain control of target creature an opponent controls until end of turn

Set: Mercadian Masques Type: Enchantment Rarity: Uncommon Cost: {U} {3}{U}{U}: Shuffle your library

An opponent chooses a nonland card exiled this way

Travel back in time to command powerful artifacts and giant robots

Leviathan [Fourth Edition (Foreign Black Border)] Rogue Rat Sacrifice another Serpent or Squirrel:Set: Fourth Edition (Foreign Black Border) Type: Creature Leviathan Rarity: Rare Cost: {5}{U}{U}{U}{U} Trample Leviathan enters the battlefield tapped and doesn't untap during your untap step. At the beginning of your upkeep, you may sacrifice two Islands. If you do, untap Leviathan. Leviathan can't attack unless you sacrifice two Islands. (This cost is paid as attackers are declared.)