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.
Spend only black mana on X. Drain Life deals X damage to any target. You gain life equal to the damage dealt, but not more life than the player's life total before the damage was dealt, the planeswalker's loyalty before the damage was dealt, or the creature's toughness.