Shadow of No Tomorrow

Look at top four cards in your library. You may
reveal a dragon among them. A dragon revealed
this way costs half of its constructed mana
value this turn, rounded down. You may pay said
mana value to cast revealed spell until the end
of your upkeep.
"There is no medicine like hope, no incentive so great,
and no tonic so powerful as expectation
of something better tomorrow." - Orison Swett Marden