Walking Ballista (Future Sight) [Mystery Booster 2] Serpent and it's attacking that player

and it's attacking that player

return target creature card from your graveyard to the battlefield tapped and attacking

Set: Betrayers of Kamigawa Type: Legendary Artifact — Equipment Rarity: Rare Cost: {2} Whenever equipped creature deals combat damage

While it's phased out

Walking Ballista (Future Sight) [Mystery Booster 2] Serpent and it's attacking that playerSet: Mystery Booster 2 Type: Artifact Creature Construct Rarity: Rare Cost: {X}{X} Walking Ballista enters 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.