Walking Ballista [Aether Revolt] SV56 and "At the beginning of

and "At the beginning of your upkeep

change all face-up monsters on the field to face-down Defense Position

Set: Sword & Shield: Base Set Type: Fighting Rarity: Ultra Rare Retreat cost: Colorless

You can send "Umi" you control to the Graveyard to send all cards in both players' hands and on the field to the Graveyard

and the howl in its throat

Walking Ballista [Aether Revolt] SV56 and "At the beginning ofSet: 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.