Echoing Calm [Darksteel] Urza's Saga Nightmare's power and toughness are

Nightmare's power and toughness are each equal to the number of Swamps you control

sacrifice it unless you pay its echo cost

Set: Magic Origins Promos Type: Legendary Creature — Sphinx Rarity: Rare Cost: {5}{U}{U} Flying

Set: Rise of the Eldrazi Type: Instant Rarity: Common Cost: {2}{U}{U} Counter target spell

Exile the token at the beginning of the next end step

Echoing Calm [Darksteel] Urza's Saga Nightmare's power and toughness areSet: Darksteel Type: Instant Rarity: Common Cost: {1}{W} Destroy target enchantment and all other enchantments with the same name as that enchantment. A single light unleashes a hail of cleansing.