Arathorn, The captain

when this creature enters the battle field you may search your library for card named 'blade of duality'. if you search your library this way shuffle. if you don't search your library this way draw a card
whenever this creature attacks, flip a coin. On heads, it gains 'this creature cannot be blocked' until end of turn and on tails untap it and it gains +1/+3 until end of turn.