Nightmare [Alpha Edition] Urza's Legacy Set: Alpha Edition Type: Instant

Set: Alpha Edition Type: Instant Rarity: Rare Cost: {W} Target spell or permanent becomes white

If it doesn't

Sun Empire commanders are well versed in advanced martial strategy

Set: Amonkhet Invocations Type: Instant Rarity: Mythic Cost: {U} Change the target of target spell with a single target unless that spell's controller pays {2}

When Dragonlord Atarka enters the battlefield

Nightmare [Alpha Edition] Urza's Legacy Set: Alpha Edition Type: InstantSet: Alpha Edition Type: Creature Nightmare Horse Rarity: Rare Cost: {5}{B} Flying (This creature can't be blocked except by creatures with flying or reach.) Nightmare's power and toughness are each equal to the number of Swamps you control. The Nightmare arises from its lair in the swamps. As the poisoned land spreads, so does the Nightmare's rage and terrifying strength.