Voidring Dragon

Flying, Rush {3}{u}{r} (Pay {3}{u}{r}, Put this card from your hand onto the battlefield. It gains Haste. Sacrifice it at the end of the turn.)
When you cast an instant or sorcery spell, draw a card for each spell you have cast this turn.
When Voidring Dragon dies, it deals X damage to target creature where X is the number of cards in your hand.