Walking Ballista [Aether Revolt] Future Sight As long as the top

As long as the top card of your library is black

Level up only as a sorcery

where X is the number of spite counters on Curse of Vengeance

Sacrifice Engineered Explosives: Destroy each nonland permanent with mana value equal to the number of charge counters on Engineered Explosives

they tap all lands with mana abilities they control and lose all unspent mana

Walking Ballista [Aether Revolt] Future Sight As long as the topSet: Aether Revolt Type: Artifact Creature Construct Rarity: Rare Cost: {X}{X} Walking Ballista enters the battlefield with X +1 +1 counters on it. {4}: Put a +1 +1 counter on Walking Ballista. Remove a +1 +1 counter from Walking Ballista: It deals 1 damage to any target.