The Rippling Well

When The Rippling Well enters the battlefield pay {x}, sacrifice X creatures and/or pay X life. Apply the following effects:
•Search your library for a creature card mana value {x} or less, reveal it and put it into your hand.
•Return target creature from your graveyard with mana value equal to the number of creatures you've sacrificed this turn.
•Give target creature an opponent controls -X/-X, where X is equal to the amount of life you've lost this turn.