Deal with the Devil

As an additional cost to cast this spell pay {x} life.
At the beginning of your upkeep double {x} and
pay {x} life.
Once per turn, you may search your library for
any card with converted mana costs {x} or less, reveal it,
and put it into your hand. Then shuffle your library.
When Deal with the Devil leaves the battlefield
you lose half your life rounded down.