Leviathan [The Dark] European Land Program put an age counter on

put an age counter on this permanent

remove a time counter

Set: New Phyrexia Type: Legendary Creature — Praetor Rarity: Mythic Cost: {5}{B}{B} Swampwalk (This creature can't be blocked as long as defending player controls a Swamp

Set: Legions Type: Creature — Sliver Rarity: Rare Cost: {3}{W} Whenever a Sliver deals damage

Set: Amonkhet Invocations Type: Legendary Creature — God Rarity: Mythic Cost: {3}{U}{B} At the beginning of your upkeep

Leviathan [The Dark] European Land Program put an age counter onSet: The Dark 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.)