Walking Ballista [Aether Revolt Prerelease Promos] Turtle put them onto the battlefield

put them onto the battlefield tapped

Sacrifice Powder Keg: Destroy each artifact and creature with mana value equal to the number of fuse counters on Powder Keg

prevent that damage

At the beginning of the upkeep of enchanted land's controller

is the chaos of a thundercloud

Walking Ballista [Aether Revolt Prerelease Promos] Turtle put them onto the battlefieldSet: Aether Revolt Prerelease Promos 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.