Sakashima the Impostor [Mystery Booster] Draft Booster Flashback {1}{G} (You may cast

Flashback {1}{G} (You may cast this card from your graveyard for its flashback cost

Set: Betrayers of Kamigawa Type: Instant — Arcane Rarity: Rare Cost: {X}{U}{U} You may exile a blue card with mana value X from your hand rather than pay this spell's mana cost

Thus the volume you hold was written

Set: HeartGold & SoulSilver: Triumphant Type: Darkness Rarity: Ultra Rare Retreat cost: Colorless

Young Conquerer enters the battlefield

Sakashima the Impostor [Mystery Booster] Draft Booster Flashback {1}{G} (You may castSet: Mystery Booster Type: Legendary Creature Human Rogue Rarity: Rare Cost: {2}{U}{U} You may have Sakashima the Impostor enter the battlefield as a copy of any creature on the battlefield, except its name is Sakashima the Impostor, it's legendary in addition to its other types, and it has "{2}{U}{U}: Return this creature to its owner's hand at the beginning of the next end step."