Matilda's Visions

As an additional cost to cast Matilda's Visions,
discard a card.
At the beginning of your upkeep, look at the top
X cards of target opponent's library, where X is
the converted mana cost of the discarded card.
You may put any number of those cards on the
bottom of that player's library, or put them back
in any order.
Matilda's visions would leave mortals paralyzed.