Kayla, The Imprisoned

+1: Add two mana of any one colour. Spend this mana only to cast creature spells, until end of turn, creature spells you cast can't be countered.
-2: Search your library for a creature card with power 4 or greater, put it into your hand, then discard a card.
-7: Put any number of creatures from your hand onto the battlefield, creatures you control gain haste until end of turn, then transform Kayla.