Whir of Invention [Aether Revolt Prerelease Promos] Planechase 2012 Set: Commander's Arsenal Type: Enchantment

Set: Commander's Arsenal Type: Enchantment Rarity: Common Cost: {2}{U} Whenever an opponent casts a spell

No more than one creature can block each combat

and all seem to owe him favors

unless you pay {B}{B}{B}

where X is 2 plus the sacrificed creature's converted mana cost

Whir of Invention [Aether Revolt Prerelease Promos] Planechase 2012 Set: Commander's Arsenal Type: EnchantmentSet: Aether Revolt Prerelease Promos Type: Instant Rarity: Rare Cost: {X}{U}{U}{U} Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.) Search your library for an artifact card with mana value X or less, put it onto the battlefield, then shuffle.