Mausoleum Secrets (Promo Pack) [Guilds of Ravnica Promos] Arrow Attack;Attack Set: March of the Machine:

Set: March of the Machine: The Aftermath Type: Legendary Creature — Dragon Avatar Rarity: Rare Cost: {W}{U}{B}{R}{G} Flying

Set: The Brothers' War Commander Type: Land — Plains Island Rarity: Rare ({T}: Add {W} or {U}

Set: Commander 2014 Type: Legendary Creature — Goblin Rarity: Rare Cost: {2}{R} Haste

it enters the battlefield as a copy of one of those cards with a number of additional +1/+1 counters on it equal to the power of the other card

At Nahiri's call

Mausoleum Secrets (Promo Pack) [Guilds of Ravnica Promos] Arrow Attack;Attack Set: March of the Machine:Set: Guilds of Ravnica Promos Type: Instant Rarity: Rare Cost: {1}{B} Undergrowth Search your library for a black card with converted mana cost less than or equal to the number of creature cards in your graveyard, reveal it, put it into your hand, then shuffle your library.