Casper, Limited Fanatic

At the beginning of your upkeep, choose constructed or sealed. If you chose sealed, skip
your next draw step and choose 10 cards at
random from the cube. Reveal those cards, and
put one into your hand. Shuffle the remaining
cards back into the cube.
{w}{u}{r}{t}: You may use mana as though it were
mana of any color to cast cards from the cube
until end of turn.