Behind the Mask [MKM - 39]

Rarity: C #: 39 Creature Type or Sub Type: Instant Rules Text Contains: As an additional cost to cast this spell, you may collect evidence 6.(To collect evidence 6, exile cards with total mana value 6 or greater from your graveyard.) Until end of turn, target artifact or creature becomes an artifact creature with base power and toughness 4/3. If evidence was collected, it has base power and toughness 1/1 until end of turn instead.