(Unreliable) Deck of Cards

{u}{r}{x}: Scry X. If the total converted mana costs of those cards minus the amount of times you have used this ability before was (only one)-
3 or less: You lose X life.
4 - 8: You may discard a card. If so, draw a card.
9 - 15: You gain 3 life.
16 or more: Search any library, graveyard, exile, or hand for a spell. You may cast that spell without playing it's mana cost. Cascade.